CATDOLL : CATDOLL: How to distinguish male and female depth bombs (ornamental small puffer fish)

How to distinguish male and female depth bombs (ornamental small puffer fish)

That is also called green pufferfish. Unfortunately, you can't tell the male from the female. You can only tell the difference when it is an adult. And don't keep it with other fish. It is ferocious. It opens its eyes and is poisonous when it grows up. It closes early and eats shrimps and small fish. It doesn't like to eat bloodworms. It is very difficult to keep. I have kept one and it died.

Sorry, I'm here to help you gain popularity, but I've only drunk depth charges, I've never raised one...

The "depth charge" pufferfish generally refers to the submarine fish, also known as the green pufferfish. It is difficult to distinguish between male and female submarine fish at ordinary times, but the male fish in estrus is brighter in color than the female fish, and the center of the outer edge of the tail fin becomes pointed, while the female fish's tail fin is still round, and the dorsal and anal fins are more rounded and blunt. The male and female fish are similar in length and size, but the female fish has a swollen abdomen.

Green river is also called submarine fish, golden doll, dog head, chicken bubble fish, belongs to the family of ornamental fish, and can be called spotted green river. The scientific name is Tetraodon nigroviridis. In the wild, it can grow up to 17CM, but in the aquarium, the big hail tank usually does not grow that big, and most of the ones sold on the market are about 5CM. It is a very popular family of ornamental fish in the current tropical ornamental fish group, and belongs to the same family as the river. The juvenile is non-toxic (about 3cm), and the adult is poisonous.

Information about whales

[Edit this section] Introduction to whales

The giant beasts of the ocean - cetaceans

The Latin name of whales is derived from the Greek word for "sea monsters", which shows the awe that the ancients had for these huge creatures that live in the ocean. In fact, the body shapes of whales vary greatly, with small ones only about 1 meter long and the largest ones over 30 meters long. Most of them live in the ocean, and only a few species live in freshwater environments. Their body shapes are very similar to those of fish, and they are streamlined and suitable for swimming, so they are commonly called whales, but this similarity is just a convergence phenomenon in biological evolution. Because whales have the characteristics of viviparity, lactation, constant temperature and breathing with lungs, which are completely different from fish, they are mammals. A whale's heart beats only 10 times a minute.

[Edit this paragraph] Characteristics of whales

The common feature of whales is that their body temperature is constant, about 36.0℃. Their skin is bare and hairless, with only a few bristles on the snout. They have no sweat glands or sebaceous glands. The fat under the skin is very thick, which can maintain body temperature and reduce the body's specific weight in water. The skull is well-developed, but the brain is small and the face is large. The frontal bone and maxilla are significantly elongated, forming a very long snout. The neck is not obvious, the cervical vertebrae are fused, and the head is directly connected to the trunk. The forelimbs are fin-shaped, the toes are not separated, there are no claws, and the elbow and wrist joints cannot move flexibly, which is suitable for swimming in water. The hind limbs are degenerate, but there are still traces of the pelvis and femur, which are residual bone pieces. The tail degenerates into a fin, and the skin at the end expands horizontally to the left and right to form a pair of large tail lobes, but they are not supported by bones. The vertebrae gradually become thinner in the narrow tail stem and finally disappear before entering the tail fin. The tail fin is different from that of fish. It can swing up and down and is the main organ for swimming. Some species also have a dorsal fin to balance the body. Their bones have spongy tissue and there is more fat in the body cavity, which can increase the body volume, reduce the body weight and increase buoyancy.

Their eyes are very small, without tear glands and nictitating membranes, and their vision is poor. They have no external ear shells, and their external auditory canals are also very thin, but their hearing is very sensitive, and they can sense ultrasound, relying on echolocation to find food, contact companions or escape from enemies. There are 1-2 external nostrils located on the top of the head, commonly known as blowholes. Generally, the more the nostrils are located at the back, the higher the degree of evolution. They breathe with lungs, one on each side, which have many capillaries, which are elastic and can help oxygen circulation, adapting to gas exchange on the water surface. They need to surface for breathing every once in a while, and can also dive for a long time. There are 10 to 20 pairs of ribs. The stomach is divided into 4 chambers. Most of the kidneys are tumor-shaped. The testicles of male animals are located in the abdominal cavity. Female animals give birth and breastfeed in water. The uterus is bicornuate, with a pair of breasts located in the cleavage on both sides of the genital fissure, with slender nipples. The milk is rich in calcium, phosphorus and a lot of fat. All calves have teeth during the embryonic period, but the teeth of baleen whales are replaced by baleen by the time they are born, while the teeth of toothed whales are retained throughout life.

Whales are mammals that live in water. They have the same physiological characteristics as terrestrial mammals, such as breathing with lungs and giving birth to live young. They also have some special physiological structures that have evolved to adapt to the aquatic environment. Whales are classified as belonging to the kingdom Animal, the phylum Chordata, the class Mammal, and the order Cetacea.

A whale's heart beats only nine times a minute. This is because whales are mammals that live in water. They have the same physiological characteristics as land mammals and breathe with lungs. They can hold their breath and slow down their heartbeats in water for a long time. That's why they can lurk in water for a long time.

The order Cetacea is further divided into two suborders, namely the Mysticeti (baleen whales) and the Odontoceti (toothed whales). The division of these two groups is mainly based on their different feeding methods. The main morphological characteristics of the Mysticeti are that they have no teeth, but have large baleen that can be used to filter plankton. Therefore, they are filter feeders. The main characteristics of the Odontoceti are that they have teeth and are predatory. The number and arrangement of their teeth vary depending on their feeding habits. There are 13 families and about 79 species in the world.

Although the word "whale" has the word "fish" in its name, it is not actually a fish, but a mammal. It has many characteristics that are very different from fish. For example, fish generally swing their tail fins left and right to move their bodies forward, while whales move forward by swinging their tail fins up and down. They use the flippers at the front to maintain body balance and control the direction of force. Some whales also have fins on the upper part of their backs that can keep their bodies vertical! The biggest difference between whales and fish is that whales have nostrils like humans and breathe with lungs, while fish breathe with gills; whales have smooth skin without scales, while fish generally have scales; whales are warm-blooded animals, while fish are cold-blooded animals; fish lay eggs, while whales give birth to baby whales directly; mother whales have two breasts under their bellies, and baby whales grow up by eating their mother's milk. When they are hungry, they use their mouths to wipe their mother's breasts, and the mother whales use strong force to spray milk directly into the baby's mouth.

Whales are herd animals. They usually live in groups in the sea. However, when whales breathe, they need to swim to the surface. They use the blowholes on their heads to breathe. When they exhale, the moisture in the air condenses and forms the familiar fountain. Experts can even identify the type of whale by the height, width and angle of the water spray! There are many types of whales, which can be roughly divided into two categories: toothed whales and baleen whales.

There is a very thick layer of fat under the skin of whales, which is commonly known as whale oil. It can keep the whale body warm and store energy for emergency use. Because whales have many special structures in their bodies, they can hold their breath and slow down their heartbeats for a long time in the water. Therefore, when they sink to the bottom of the sea, they always have to wait for a long time before they surface again. In addition to having a structure to store oxygen, when a certain part of the body needs a large amount of blood supply, there is also a special function in the body to concentrate the supply!

The water column sprayed by baleen whales is tall and thin, while the water column sprayed by toothed whales is thick and short. Some people can even judge the type of whale based on the water column!

Whales are mammals that live in the ocean. Some whales are very large, with the largest reaching 30 meters in length. The body of a whale is like a fish, fusiform. It has a large head, small eyes, and completely degenerate ear shells. The neck is not obvious. The forelimbs are fin-shaped, and the hind limbs are completely degenerate; most species have fins on their backs; the tail is horizontally fin-shaped and is the main organ of movement. There are teeth or no teeth. There are one or two nostrils, which are opened on the top of the head. Adults are hairless (many species only have some hair around their mouths). There is a thick layer of fat under the skin, which can keep warm and reduce the specific gravity of the body. It breathes with lungs, and dives into the water after inhaling air on the surface, and can swim underwater for 10 to 45 minutes. It generally feeds on zooplankton, mollusks and fish. It is viviparous, usually giving birth to one calf per litter, and feeds the calf with milk. But many people classify them as fish, but in fact they are not fish but mammals. They are distributed in oceans around the world.

Whales are distributed in all oceans of the world. They are aquatic mammals that breathe with lungs. There are two types of whales: baleen whales, which have no teeth, baleen, and two nostrils, such as fin whales, blue whales, humpback whales, and gray whales; and toothed whales, which have teeth, no baleen, and one nostril, such as sperm whales, narwhals, and killer whales. Most of the oxygen in the ocean and 60% of the oxygen in the atmosphere are produced by phytoplankton. Baleen whales can kill zooplankton, the enemy of phytoplankton. In addition, toothed whales also help maintain the ecological balance of fish. Toothed whales feed on large mollusks that feed on fish. Therefore, if there are no whales in the world, humans will perish.

Whales have a very poor reproductive capacity, giving birth to a calf every two years on average. Due to human hunting and environmental pollution, the number of whales has been drastically reduced. For example, nearly 360,000 blue whales were killed in the 20th century, and there are less than 50 left today. Many species of whales, which have lived on Earth for more than 50 million years, are now on the verge of extinction.

The ancestors of whales were originally animals that walked on land with four limbs. They were probably insectivores or carnivores who lived mainly on the coast. Later, they were attracted by fish and other food in the water. After a long time, they returned from land to the sea and gradually adapted to marine life. The earliest whales were the protocetids, protodontids, and protocetids in the middle of the Eocene Epoch, about 55 to 36 million years ago. Compared with the existing whales, they have smaller skulls, nostrils located in the front of the head, and have not yet moved to the top of the head. Their teeth are similar to those of ancient insectivores and carnodonts, with 44 or less teeth. Their tooth shapes and skulls are also very similar. There are only a few differences, but they already have a body shape similar to fish that is adapted to living in seawater.

"The appearance of tail fins may have been the final step in the transition of whales from land to sea," explained paleontologist Mark Euhorn of the Alabama Museum of Natural History. Euhorn analyzed recently discovered fossils to explore this mysterious process. The fossils were found by amateur bone enthusiasts on the banks of rivers in Alabama and Mississippi. They are bones formed after the death of the ancient whale Volotegeorgia. Volotegeorgia lived about 40 million years ago and swam in the Gulf of Mexico in North America. This ancient whale was about 3.7 meters long and mainly relied on its sharp teeth to prey on fish. The earliest known whale with tail fins is closely related to the genus Volotegeorgia. But Euhorn found that when Volotegeorgia split from other whales just 2 million years ago, it was obviously without tail fins.

Euhorn focused on analyzing a newly discovered tail vertebra that is about 5 cm long. This vertebra is one of the approximately 20 tail vertebrae of Volot Georgiacetus. After analysis, it was found that this vertebra is not similar to the vertebrae near the whale's tail. Therefore, Euhorn believes that Volot Georgiacetus mainly relies on swinging its hind legs to swim. Previous studies have also believed that this ancient whale had huge hips, indicating that they also had huge hind legs. Strangely, scientists have also found that their pelvis is not connected to the spine. Until now, this phenomenon remains an unsolved mystery. Euhorn said, "The point we have confirmed is that this ancient whale mainly relied on swinging its hips and paddling its feet to swim in the water. This is very similar to the way modern whales swim, but modern whales mainly rely on the ups and downs of their bodies to swim."

In the history of biological evolution, there has always been a missing link from ancient terrestrial quadrupeds to today's aquatic mammals. Therefore, scholars believe that the ancient whale fossils discovered above just fill this gap. However, why did the ancient whales move from land to water? It turns out that the reproduction and feeding of ancient whales were all carried out on land, just like today's amphibians such as sea lions, fur seals, and seals. However, the evolution of organisms is often affected by environmental changes. About 50 million years ago, because the ratio of food and predators in the water was easier for ancient whales to survive than on land, they began to enter the water; about 10 million years ago, the descendants of ancient whales evolved to be very similar to modern whales, with tails and short necks, and their hind feet also degenerated into fin-like appendages, and they no longer came ashore.

[Edit this paragraph] Types of whales

Baleen whales are huge, with the smallest species being more than 6 meters long. There are no teeth in the mouth, and only degenerate teeth can be seen during embryonic development. However, there are 150-400 horny whiskers arranged in a comb-like pattern from the palate to the pharynx on both sides of the upper jaw. The color, shape and number of whiskers vary from species to species, and are one of the important bases for classification. There are two external nostrils located on the top of the head, which can spray two jets of water when breathing. The skull is extremely large, and some species can reach 1/3 of the body length, and are symmetrical. The cervical vertebrae are fused or separated. The sternum is small, with only 1-2 pairs of ribs connected to the sternum, and the thorax is incomplete. There is no clavicle. The flippers generally have 4 fingers. There is a cecum in the digestive tract. It mainly feeds on small crustaceans such as krill, and some species also eat small schooling fish, as well as bottom-dwelling fish and shellfish. There are three families of baleen whales in the world: right whales, gray whales and fin whales, with a total of about 6 genera and 11 species.

Toothed whales have a large variation in body shape. The smallest species is only about 1 meter long, and the largest is more than 20 meters long. They have conical teeth in their mouths, but the shape and number of teeth of different species vary greatly. The smallest has only one single tooth, and the largest has dozens of teeth. Some are hidden in the gums and are not exposed, so they are also one of the important bases for classification. There is only one external nostril, so it can only spray a stream of water when breathing. The skull is asymmetrical. There are 5 fingers on the flippers. The sternum is large. There is no clavicle. There is no cecum. They mainly feed on squid, fish, etc., and some can also prey on seabirds, seals and other large animals such as other whales. There are 8 families of toothed whales in the world, including pufferfish, sperm whales, sword-beaked whales, narwhals, sharp-nosed dolphins, porpoises, dolphins and pilot whales, with about 34 genera and 72 species.

The blue whale is the largest mammal in the world. It can grow up to 30 meters long and weigh an average of 150 tons. Its mouth can be opened wide enough for 10 adults to enter and exit freely. The blue whale is full of treasures. Its fat can be used to make soap; its meat is nutritious; its bones can be used to extract glue; its liver contains a lot of vitamins; and its blood and internal organs are high-quality fertilizers.

Ancestors of whales

"Ambiuro Keitaus"

About 1 million years after the appearance of Pachicataeus, whales took another step towards the ocean. The representative animal of this stage is a 4-meter-long "Ambilocaetus", which means amphibious whale or walking whale. If Pachicataeus is similar to a wolf, then Ambilocaetus is similar to a crocodile. Ambilocaetus was discovered earlier than Pachicataeus. Researchers believe that Ambilocaetus is a transitional animal in the development of whales.

The biggest ecological feature of Ambiurocetaus is that it lives in the sea and on land, mostly eating marine fish and drinking seawater. It is generally believed that all mammals form teeth and bones through oxygen atoms in water molecules in food. Oxygen exists in three isotopes in nature, and when they have a specific ratio, the ratio in seawater and freshwater is different. Therefore, when analyzing the skeletal fossils of Ambiurocetaus, it shows that the isotope ratio of freshwater is higher, which means that Ambiurocetaus ate animals on land, thus creating its own bones and body shape.

Its ecology is somewhat similar to that of modern crocodiles. Its eyes are very small. If its body is in the sea, its eyes are above the water surface to observe the surrounding situation. Analysis of its skeleton shows that its hind toes are long for swimming in the water, and its front toes are not so long, which is convenient for crawling out. They often lurk in shallow waters, keeping an eye on all directions, waiting for an opportunity to attack passing animals.

"Lodekaitaus"

After Ambiurocaetus, an animal with the appearance and size of an otter and Rhodecaetus, which still retained many characteristics of Ambiurocaetus, appeared one after another, and other ancestors of whales appeared one after another. Moreover, this Rhodecaetus animal is believed to have fully adapted to living in the water. It took about 3 to 4 million years from the appearance of Pakicataetus to the appearance of Rhodecaetus. However, this is a brief moment in paleontology.

Dalton and Losaurus Brazil

About 39 million years ago, whales with streamlined bodies and able to swim smoothly in the ocean, such as Dalton and Losaurus brasiliensis, appeared. They no longer had the long tails of their ancestors, but instead had tail fins. Dalton, 4.5 meters long, had skeletons similar to those of modern dolphins, but with some traces of degeneration of the hind legs. Losaurus brasiliensis had an eel-like slender body, about 18 meters long, which was larger than most whales in the world today. But it also had two small hind legs.

Whales such as Basilisk and Loxasaurus are all called extinct species of protocetids in taxonomy. Among them, Dalton, which has more modern whale body characteristics, later evolved into modern toothed whales and baleen whales. However, scientists believe that no animal bone fossils related to Dalton and modern whales have been found.

However, it is generally believed that the global sea level dropped when protocetids evolved into baleen whales and toothed whales, which was about 34 million years ago. There should be many places in the world where the strata can be excavated at this time. If people are lucky, they will find fossils of transitional species from protocetids to modern whales sooner or later.

[Edit this paragraph] The value and protection of whales

Whales have been hunted by humans since ancient times due to their great economic value. However, due to backward hunting methods, the amount of hunting was small in the past, which was not enough to affect the number of whales. In modern times, people have switched to using ships and artillery to hunt whales, which has greatly increased the lethality, causing a sharp decline in the number of whales, and many species are on the verge of extinction.

Now, as countries around the world have imposed strict restrictions on the number of whales caught each year, whaling is no longer a major concern for scientists who monitor the number and survival of whales. However, in the entire world, the unprecedented marine pollution caused by human economic development has posed a great threat to whales, and the degree of the threat is far greater than that of hunting. In addition, the rapid development of industrialized fishing has also greatly affected the food source of whales and other marine mammals, which is another major factor affecting their survival. People used to imagine the ocean as a vast and free world and a symbol of adventurous activities. Therefore, while plundering marine resources unscrupulously, not only is there a lot of ocean noise generated by the shipping industry and a large amount of ballast water discharged every year, but also a large amount of garbage is dumped into the ocean. About 100,000 chemicals have also reached the ocean through sewage discharge and air. Difficult to decompose organic chlorides have increased the content of marine organic matter, making marine pollution more and more serious and bringing serious consequences.

The results of modern scientific research show that the ocean is a giant container for storing waste gas carbon dioxide. The cold and hot ocean current systems have a great impact on the earth's climate. In the deep sea, which has not been studied much, there are many unknown animals and plants that are beneficial to humans, including many potential sources of food and medicine for humans, which are of great value. The increasing degree of marine pollution will destroy these precious resources. Due to the destruction of the ozone layer, the population density of krill living in the waters around Antarctica has dropped sharply. The number of krill per 1,000 cubic meters of seawater has dropped sharply from 177.8 before 1982 to 1984 to 41.2 from 1984 to 1985. Krill is a crustacean in the ocean and an important bait for marine fish, whales and other marine mammals. It has an extremely important position in the marine food chain. Moreover, it has also attracted great attention as the largest protein resource remaining on the earth. Since marine mammals such as whales are at the end of the food chain, marine pollution, especially irritating substances such as heavy metal pollution, seriously weakens their immune systems, making them extremely vulnerable to attacks by viruses and bacteria. Pollution also prevents females from conceiving or causes miscarriage, greatly reducing their reproduction rates.

Whales have a very poor reproductive capacity, giving birth to one baby whale every two to three years on average...Due to human hunting of whales and pollution of the marine environment...the number of whales has gradually decreased...For example, 360,000 blue whales were slaughtered in the 20th century!!! There are less than 50 left now~! Many species are on the verge of extinction...

[Edit this section] Whales in my country

my country has abundant cetacean resources. So far, 9 families, 26 genera and 38 species have been found in my country's waters, including blue whales with a body length of more than 30 meters and finless porpoises with a body length of only about 1 meter. In particular, we also have a unique freshwater cetacean - the white-fin dolphin (extinct), which is a rare gem among cetaceans. Except for the white-fin dolphin and the Chinese white dolphin, which are listed as first-class protected animals in my country, all other species of cetaceans in China are listed as second-class protected animals.

my country has discovered a whale weighing nearly four tons, about 17 meters long, whose tongue alone weighs as much as a dozen large fat pigs! It is spacious enough for four people to sit inside and read.

[Edit this section] Whale stranding in China

On the morning of March 28, 2008, a whale carcass was washed up on the beach of Sanya Bay in Sanya City. The carcass has begun to rot, and the cause of death and the specific species are not yet determined. Previously, a large group of whales were stranded and died in Australia. There should be more and more attention paid to protecting whales!

This is not the first time that a whale has been stranded in my country. It happens even more frequently in the world, and the reasons behind it are thought-provoking.

On March 10, 2005, a whale 8 meters long and weighing about 4 tons was stranded and died in Wuchuan, Guangdong.

A giant whale, a national first-class marine protected animal, which was more than 8 meters long and weighed about 4 tons, was found stranded and dead on the coast near Liangmei Village, Dashanjiang Street, Wuchuan City on the afternoon of March 10, 2005.

On March 11, 2008, a whale weighing more than 2 tons was stranded and died in Hainan.

In the early morning of March 11, 2008, a whale weighing more than 2 tons was found stranded and dead in the Chaotan Port of Jinshan Town, Wenchang City, Hainan Province. At present, the relevant departments have buried the whale and will extract the skeleton of the fish to make a specimen for research.

September 1, 2008, a 3,000-pound whale was stranded on Golden Beach

According to the Qingdao Morning Post, on the evening of August 30, 2008, an adult Japanese beaked whale weighing 3,000 kilograms was stranded in the Golden Beach area of ​​Qingdao Development Zone.

【Cause Exploration】

[1] Even giants are helpless: the helplessness behind whale strandings

What exactly causes such tragedies to happen so frequently? Let’s see what the experts say.

Is the whale confused?

Scientists have not been able to explain why these whales are stranded, but most explanations are related to the echolocation system in their bodies. The eyes of a giant whale are only as big as a small watermelon, and its vision is extremely degraded. Generally, it can only see objects within 17 meters, which is very inconsistent with its huge body. They do not rely on their eyes to navigate, measure objects and hunt, but have a highly sensitive echo ranging ability. They emit ultrasonic waves with a very wide frequency range. When these ultrasonic waves encounter obstacles, they are reflected back to form echoes. Whales accurately judge the distance between themselves and obstacles based on the round-trip time of these ultrasonic waves.

Internal discomfort, parasites, or problems with the system itself can cause the echolocation system to malfunction, causing the whale to lose its way and run around. Some scientists also believe that when whales mistakenly enter flat waters in order to hunt, they will be stranded once the tide recedes; and when they swim into the bay to chase fish and emit ultrasonic waves toward the beach with a large slope, the echoes are often very inaccurate, or even completely unreceived, and they will lose their way. Whales are gregarious animals. If one whale runs into the beach and gets stranded, the others will follow without hesitation, causing a tragedy of group deaths and injuries.

As early as December 2004, the American magazine Science reported that according to the research of scientists from the Woods Hole Oceanographic Institution in the United States, some scientists believe that the cause of the whales' death may be that they floated to the surface too quickly. Two scientists from the institute found small pits after studying the bones of sperm whales that died from stranding. They explained that this was a phenomenon of bone necrosis in the bones of sperm whales. Sperm whales can dive to a depth of more than 3,200 meters underwater to hunt. If they float to the shallow sea quickly, the nitrogen in their bodies will surge out to form bubbles. These bubbles entangled in the tissues will compress the nerves, block the capillaries, cause the muscles to be deprived of oxygen, and even affect the bones to cause regional necrosis, leaving multiple small pits. This shows that the "suicide" of sperm whales is likely the price they pay for rising too quickly when foraging.

Is nature also contributing to the problem?

In 1997, about 300 whales committed mass suicide off the coast of the Falkland Islands. Argentine scholars analyzed the situation and believed that the intense activity of sunspots at that time caused anomalies in the geomagnetic field and a "geomagnetic storm", which destroyed the echolocation system of the migrating whales and caused them to make "directional" errors.

Experts at the National Marine Aquarium in the UK have also speculated that the sound shock waves generated by low-frequency earthquakes on the seabed may have interfered with the echolocation systems of these mammals, causing them to mistakenly go to the beach.

Is it humans' fault again?

Environmental pollution is also considered by environmentalists and scientists to be the cause of whale strandings. Scientists believe that chemicals that pollute the seawater may disrupt the whales' senses. In addition, Dr. Collet, deputy director of the La Rochelle Marine Mammal Research Center in France, believes that the sound waves emitted by warship sonars and echo sounders and the noise of underwater explosions can disrupt the whales' echolocation system.

A few years ago, the U.S. Navy used large sonar equipment in the deep sea off Panama Island, and then some whales and dolphins were stranded and died. Investigators from the National Marine Fisheries Service and the Navy said that the noise from the sonar caused the death of marine life. They found that the whales' ears were severely damaged by the noise, and there were bloodstains around the whales' brains and ear bones. Scientists say that marine mammals are actually very fragile and can be frightened by the slightest disturbance. Human maritime exercises can also cause them to panic.

From the above aspects, it can be seen that the reasons for whale stranding are diverse, but to a large extent, it is also due to changes in the ecological environment. I hope that everyone can pay attention to ecological protection in the future and pay more attention to information in this regard so that such tragedies will not happen again.

The Latin name of whales is derived from the Greek word for "sea monsters", which shows the awe that the ancients had for these huge creatures that live in the ocean. In fact, the body shapes of whales vary greatly, with small ones only about 1 meter long and the largest ones over 30 meters long. Most of them live in the ocean, and only a few live in freshwater environments. Their body shapes are very similar to those of fish, and they are streamlined and suitable for swimming, so they are commonly called whales, but this similarity is just a convergence phenomenon in biological evolution. Because whales have the characteristics of viviparity, lactation, constant temperature and breathing with lungs, which are completely different from fish, they are mammals. A whale's heart beats only 9 times a minute.

From an anatomical point of view, many characteristics of whales show a high degree of adaptation to life in the sea. However, anatomical evidence is not enough to answer many questions about the origin of whales. However, from a biochemical and genetic point of view, whales are closely related to ungulates, and the fossil record (about 50 million years ago) also supports that whales evolved from ungulates.

The ancestors of whales are most likely terrestrial ungulates found in North America, Europe, and Asia - the Mesonychidae family. Some members of the Mesonychidae are as small as domestic dogs, while others are as large as bears. However, many animals evolve from small to large, so whales may have evolved from small Mesonychidae.

It is speculated that these mesonychids, which had few teeth and fished in shallow waters, gradually transformed into an amphibious lifestyle and then, in the long process of evolution, became today's various whales and dolphins.

It is currently known that the earliest whales were the Protocetidae family of the Archaeocetes suborder.

Protocetidae all appeared 50 million years ago, and their fossils are found in Asia, Africa, and North America. Scientists know more about Pakicetus, which was found in present-day Pakistan. This fossil, which lived 53-50 million years ago, was an animal with a blowhole (nostril) that had moved to the back, a narrow brain ventricle, and still had hind limbs. Fossil evidence found in Indian rock formations of the same period also shows that there was already an unimaginable high degree of ecological diversity among early whales.

The more advanced Archaeocetes are the Basilosauridae, which were once identified as reptiles. The animals of this family lived about 45-38 million years ago. Although they were first discovered by American geologists in Louisiana, similar fossils have also been widely found in New Zealand and even Antarctica. This discovery shows that Archaeocetes had spread to southern waters 40 million years ago.

Another branch of the more advanced Archaeocetes, the Dorudontinae, includes at least six species. They have narrower jaws, which may be for filter feeding; or, like most living toothed whales, they can use this structure to quickly clamp fish, squid, and birds.

After a long evolutionary process, the Archaea finally went extinct in the Oligocene. However, the other two branches of the whale family, the Mysticeti and Odontoceti, have gone beyond the past and derived 13 families and nearly 80 species of fascinating creatures, enriching our marine vitality.

【Morphological characteristics】

A completely aquatic mammal. The body length is 1 to 30 meters, the body is similar to that of a fish, the skin is naked, only a few hairs are on the snout, and there are no sweat glands and sebaceous glands. The forelimbs are fin-shaped, the hind limbs are completely degenerate, and there is only a pair of small bones in the body. The skin at the end of the tail expands to the left and right to form a horizontal tail fin. There are no auricles, because there is a thick layer of fat under the skin, which keeps warm and reduces the body weight, which is conducive to swimming. Some species have dorsal fins. The eyes are small, there is no nictitating membrane, and there is no tear gland. The vision is poor, and some mainly rely on echolocation to find food and avoid enemies. There are 1 to 2 external nostrils, located on the top of the head, commonly known as blowholes. Although there are no auricles, the hearing is sensitive. There is one lobe on each side of the lung. It breastfeeds in water. The stomach is divided into 4 chambers. It generally feeds on mollusks, fish and zooplankton. Some species can also prey on seals, fur seals, etc. Distributed in oceans all over the world.

【Biological description】

Like all mammals, whales breathe with lungs and are warm-blooded. Their young are fed by breast milk and have a little hair. Their lungs are large, and they breathe thoroughly with each breath. They use oxygen economically after diving, so whales can dive for 30 to 70 minutes, or even longer, before surfacing to breathe. Most small whales are shallow divers, while some large whales can dive deep, such as sperm whales, which can dive 900 to 1,134 meters. The whale's forelimbs form fins, the hind limbs are completely degenerate, the tail becomes a tail fin, and the nostrils are on the top of the head. The blue whale is particularly noteworthy. It is the largest animal in the world, with a body length of up to 30 meters and a weight of 180 tons.

Whales are considered predators. Their food is very diverse, ranging from microorganisms to large fish. All mammals, including whales, need to sleep, but whales can only keep one hemisphere of their brain asleep because they try to stay awake to breathe. So whales never fall asleep but still get the sleep they need. Whales "sleep" about 8 hours a day.

The male whale uses the vas deferens to discharge sperm into the female's body. After the fertilization process is completed, the sperm and egg combine in the mother's body. The mother whale usually gives birth to one calf. The gestation period is basically about one year. Some calves may need a year of nursing, and the nursing period is longer. Some calves will even follow their mothers for several years after birth before being weaned. In their living environment, they will encounter predation by sharks, so a very strong relationship will be established between mother and child. Some whales mature very late, about seven to ten years. The reproductive organs of whales retract into the body to avoid resistance when swimming. The mother whale has a pair of nipples, and relies on the contraction of the muscles around the breasts to squeeze milk into the mouth of the calf to feed the calf. The life span of a whale is about 60 to 70 years.

【Subjects】

The order Cetacea contains about eighty species of large, placental mammals that live in the ocean. Whales belong to the order Cetacea, which also includes dolphins and small whales. The term "whale" itself is vague and can include all whales, some large ones, or those belonging to specific families. However, killer whales and pilot whales belong to the dolphins (Delphinidae). The order Cetacea is divided into two suborders: Mysticeti - baleen whales - and Odontoceti - toothed whales.

Extant species can be divided into the suborders baleen whales and toothed whales.

Mysticeti

Baleen whales comprise the largest group of living animals in the world, with three families and 10 species, all of which live in the ocean.

Balaenidae, such as: black right whale (black true whale) Eubalaena glacialis, southern right whale Eubalaena australis, Arctic right whale (humpback whale) Balaena mysticetus, small right whale Caperea marginata, right whale (Note: some are divided into small right whale family Neobalaenidae)

Gray whale family Eschrichtiidae Eschrichtius robustus

Balaenopteridae, such as: blue whale (blue whale, razorback whale) Balaenoptera musculus, minke whale (small whale) Balaenoptera acutorostrata, humpback whale (humpback whale, humpback whale) Megaptera novaeangliae, Fin whale, Fin whale (whale), Bryde's whale (whale), Bryde's whale Balaenoptera edeni, Sei whale

They are huge in size, with the smallest species being more than 6 meters long. They have no teeth in their mouths. There are 150 to 400 horny baleen on each side of the upper jaw. The color, number and shape of the baleen vary from species to species and are an important basis for classification. There are two external nostrils located on the top of the head. The head is extremely large, with some species reaching 1/3 of the body length. There are only 1 to 2 pairs of ribs connected to a small sternum, no clavicles, and flippers generally have 4 fingers. They have a cecum. They use baleen to filter plankton from seawater. They feed on krill and cephalopods, and some also eat small fish and bottom-dwelling shellfish.

Odontoceti

Only a few species of toothed whales live in fresh water, and most of them live in the ocean. There are 7 families and more than 80 species. (Note: There are some different opinions on the classification of toothed whales. They can be roughly divided into three relatively different groups: dolphins, beaked whales and sperm whales, each of which is divided into one or more families.)

The family Platanistidae is also known as the freshwater dolphin family. For example: Lipotes vexillifer, Indus river dolphin Platanista indi, Ganges river dolphin Platanista gangetica, Amazon river dolphin Inia geoffrensis, Madeira river dolphin Inia boliviensis, La Plata river dolphin Pontoporia blainvillei.

Delphinidae, such as: true dolphin Delphinus delphis, short-beaked true dolphin Delphinus delphis Linnaeus, long-beaked true dolphin Delphinus capensis Gray, bottlenose dolphin Tursiops truncatus, Amazonian white dolphin Sotalia fluviatilis, killer whale (killer whale, killer whale) Orcinus orca, dolphin, Chinese white dolphin, giant whale (pilot whale, black round-headed whale) Globicephala melaena, big-beaked pilot whale, long-finned pilot whale, short-finned pilot whale, melon-headed whale, Arctic killer whale, false killer whale Pseudorca crassidens, pygmy killer whale. (Note: Some are divided into pilot whale family Globiphlidae)

Phocaenidae, e.g. Neophocaena phocaenoides

Monodontidae Such as Monodon monoceros, Delphinapterus leucas, (Note: Sometimes the Irrawaddy dolphin (short-beaked dolphin) Orcaella brevirostris is also included in this family.)

Hyperoodontidae, e.g. Bryde's beaked whale Mesoplodon densirostris

Physeteridae, e.g. Physeter catodon

Kogiidae, such as Kogia breviceps, Kogiasimus

They vary in size. They have teeth in their mouths and only one external nostril. They usually have five flippers. Except for the Gangetic dolphin, they have no cecum. This animal has a unique ability to sense the environment through echolocation. They mainly feed on squid, cuttlefish, crustaceans, and fish.

【Economic Value】

China is rich in whale resources and has a long history of whaling. The whales have great economic value: their meat is edible, their skin can be made into leather, their brain oil can be refined into industrial lubricants, their fat can be made into machine oil, soap, and candles, their bones can be made into bone meal, and their internal organs can be made into vitamin preparations.

【Protect】

Due to environmental degradation and large-scale hunting by humans, members of the order Cetacean, especially some large members, are widely hunted due to their high economic value, and many whales are on the verge of extinction.

The International Whaling Commission (IWC) is an international organization responsible for managing whaling and whale conservation. After commercial whaling caused a sharp decline in whale numbers, the IWC decided to take action to protect whales. This included a temporary ban on commercial whaling from 1986, and the establishment of the Indian Ocean Whale Sanctuary and the Southern Ocean Whale Sanctuary in 1979 and 1994 respectively. However, since 1986, more than 25,000 whales have been killed under the banner of "scientific whaling" because Japan and Norway have taken advantage of loopholes in the IWC resolution. The countries currently whaling include Norway, Iceland and Japan, as well as some indigenous tribes in Siberia, Alaska and northern Canada.

whale

Whales are mammals that live in the ocean. Some whales are very large, with the largest reaching 30 meters in length. The body of a whale is like a fish, fusiform. It has a large head, small eyes, and completely degenerate ear shells. The neck is not obvious. The forelimbs are fin-shaped, and the hind limbs are completely degenerate; most species have fins on their backs; the tail is horizontally fin-shaped and is the main organ of movement. There are teeth or no teeth. There are one or two nostrils, which are opened on the top of the head. Adults are hairless (many species only have some hair around their mouths). There is a thick layer of fat under the skin, which can keep warm and reduce the specific gravity of the body. It breathes with lungs, and dives into the water after inhaling air on the surface, and can swim underwater for 10 to 45 minutes. It generally feeds on zooplankton, mollusks and fish. It is viviparous, usually giving birth to one calf per litter, and feeds the calf with milk. But many people classify them as fish, but in fact they are not fish but mammals. They are distributed in oceans around the world.

Whales are distributed in all oceans of the world. They are aquatic mammals that breathe with lungs. There are two types of whales: baleen whales, which have no teeth, baleen, and two nostrils, such as fin whales, blue whales, humpback whales, and gray whales; and toothed whales, which have teeth, no baleen, and one nostril, such as sperm whales, narwhals, and killer whales. Most of the oxygen in the ocean and 60% of the oxygen in the atmosphere are produced by phytoplankton. Baleen whales can kill zooplankton, the enemy of phytoplankton. In addition, toothed whales also help maintain the ecological balance of fish. Toothed whales feed on large mollusks that feed on fish. Therefore, if there are no whales in the world, humans will perish.

We divide whales into two groups:

Odontocetes: toothed marine giants such as sperm whales, killer whales, dolphins, and porpoises.

Baleen whales: whales with baleen. These baleen are actually angled teeth that grow inside the mouth and replace teeth for filtering water and catching shrimp and other small animals that the whale eats.

Whales are viviparous mammals, not fish. A baby whale needs to feed on its mother's milk for a year before it can grow to maturity. Fish are oviparous vertebrates. Parent fish generally do not have the habit of taking care of their young. The "fins" of whales actually evolved from limbs. This is not the case with fish. Whales breathe with lungs. Fish breathe with gills. Whales are warm-blooded animals, while fish are cold-blooded animals. You cannot distinguish whales from fish by whether they have scales. This is because many fish do not have scales either.

1. Baleen whales have two different methods of hunting, depending on the species.

Skimming: Like beluga whales, they filter plankton while swimming slowly, with their mouths half open and water flowing in from the joints.

Swallowing: When this whale approaches a large patch of shrimp on the seafloor, it opens its mouth and swallows a large amount of water into its expandable, foldable stomach. When its mouth closes, its tongue rolls up the water filtered by its baleen plates. For example, a blue whale can swallow 25,000 liters of water at a time.

Every year, some whales leave the polar oceans where food is abundant to find warmer waters to give birth to their offspring. They travel thousands of kilometers over a period of several months at very specific times. Every winter, many tourists sail thousands of miles just to meet them in the Hawaiian Sea and the Gulf of Mexico. For sperm whales, males cannot migrate because they cannot find enough food such as squid in the breeding areas.

Whales are mammals that live in water all their lives. They are so dependent on water that they cannot survive once they leave the water. In order to adapt to life in water and reduce resistance, their hind limbs disappeared and their front limbs became paddles for paddling. Their bodies became streamlined, resembling fish. Therefore, they have strong diving ability. Dolphins (small toothed whales) can dive to a depth of 100-300 meters and stay for 4-5 minutes. Fin whales can stay 300-500 meters underwater for 1 hour. The largest toothed whale, sperm whale, can dive to less than 1,000 meters and stay in the water for 2 hours. In 1955, a sperm whale was found dead in the sea near Ecuador, entangled in submarine cables. Its diving depth reached 1,133 meters. A sperm whale was found suffocated by cables at a depth of 2,200 meters in the waters near the Portuguese capital of Lisbon. This is the deepest diving record of mammals so far.

2. Types of whales: As far as all marine mammals are concerned, whales are the most numerous and the largest in number. Whales can be divided into two categories: one is the type with no teeth in the mouth, but only whiskers, which is called baleen whales; the other is the type with no whiskers in the mouth but still retains teeth, which is called toothed whales. Although there are few types of baleen whales, they are huge and have become the main target of human capture. Among them are the huge and unparalleled blue whales, the slow-moving, big-headed and fat right whales, the short-bodied, long-armed humpback whales that like to swim near the shore, and the small baleen whales with small bodies and pointed snouts, etc. There are many types of toothed whales. Except for sperm whales, the rest are generally smaller, such as the extremely ferocious killer whales and dolphins. Although whales have different lengths, thicknesses, and shapes, they are all streamlined and look like fish, so people often call them whales. However, whales are mammals. Like humans, they constantly surface to breathe air. Sometimes we can see white mist columns emitted by whales when they exhale on the sea. Some of them are as high as more than ten meters, like fountains, which is very spectacular.

Whales are mammals that live in the ocean. Some whales are very large, with the largest body length reaching 30 meters and the smallest exceeding 6 meters. At present, the largest known whale weighs about 160,000 kilograms. A whale weighing nearly 40,000 kilograms and about 17 meters long was discovered in my country. The body shape of a whale is like a fish, in the shape of a spindle. The head is large, the eyes are small, and the ears are completely degenerate. The neck is not obvious. The forelimbs are fin-shaped, and the hind limbs are completely degenerate; most species have fins on their backs; the tail is horizontal fin-shaped and is the main organ of movement. There are teeth or no teeth. There are one or two nostrils on the top of the head. The whole body is hairless (many species only have some hair left around the mouth). There is a thick layer of fat under the skin, which can keep warm and reduce the specific weight of the body. Breathe with lungs, and dive into the water after inhaling air on the surface of the water. It can swim underwater for 10 to 45 minutes. It generally feeds on zooplankton, mollusks and fish. It is viviparous, usually giving birth to one baby per litter, and feeding the baby whale with milk. But many people classify them as fish, in fact they are not fish but mammals. Distributed in the world's oceans.

Whales are distributed in all oceans of the world. They are aquatic mammals that breathe with lungs. There are two types of whales: baleen whales, which have no teeth, baleen, and two nostrils. They include fin whales, blue whales, humpback whales, gray whales, etc.; toothed whales, which have teeth, no baleen, and one nostril. They include sperm whales, narwhals, killer whales, etc. Most of the oxygen in the ocean and 60% of the oxygen in the atmosphere are produced by phytoplankton. Baleen whales can kill zooplankton, the enemy of phytoplankton. In addition, toothed whales also help maintain the ecological balance of fish. Toothed whales feed on large mollusks that feed on fish. Therefore, if there are no whales in the world, humans will perish.

The common feature of whales is that their body temperature is constant, about 35.5℃. Their skin is bare and hairless, with only a few bristles on the snout. They have no sweat glands or sebaceous glands. The fat under the skin is very thick, which can maintain body temperature and reduce the body's specific weight in water. The skull is well-developed, but the brain is small and the face is large. The frontal bone and maxilla are significantly elongated, forming a very long snout. The neck is not obvious, the cervical vertebrae are fused, and the head is directly connected to the trunk. The forelimbs are fin-shaped, the toes are not separated, there are no claws, and the elbow and wrist joints cannot move flexibly, which is suitable for swimming in water. The hind limbs are degenerate, but there are still traces of the pelvis and femur, which are residual bone pieces. The tail degenerates into a fin, and the skin at the end expands horizontally to the left and right to form a pair of large tail lobes, but they are not supported by bones. The vertebrae gradually become thinner in the narrow tail stem and finally disappear before entering the tail fin. The tail fin is different from that of fish. It can swing up and down and is the main organ for swimming. Some species also have a dorsal fin to balance the body. Their bones have spongy tissue and there is more fat in the body cavity, which can increase the body volume, reduce the body weight and increase buoyancy.

Their eyes are very small, without tear glands and nictitating membranes, and their vision is poor. They have no external ear shells, and their external auditory canals are also very thin, but their hearing is very sensitive, and they can sense ultrasound, relying on echolocation to find food, contact companions or escape from enemies. There are 1-2 external nostrils located on the top of the head, commonly known as blowholes. Generally, the more the nostrils are located at the back, the higher the degree of evolution. They breathe with lungs, one on each side, with many capillaries, which are elastic and can help oxygen circulation, adapting to gas exchange on the water surface. They need to surface to exchange air every once in a while, and can also dive for a long time. There are 10 to 20 pairs of ribs. The stomach is divided into 4 chambers. Most of the kidneys are tumor-shaped. The testicles of male animals are located in the abdominal cavity. Female animals give birth and breastfeed in water. The uterus is bicornuate, with a pair of breasts located in the cleavage on both sides of the genital fissure, with slender nipples. The milk is rich in calcium, phosphorus and a lot of fat. All calves have teeth during the embryonic period, but the teeth of baleen whales are replaced by baleen by the time they are born, while the teeth of toothed whales are retained throughout life.

Whales are mammals that live in water. They have the same physiological characteristics as terrestrial mammals, such as breathing with lungs and giving birth to live young. They also have some special physiological structures that have evolved to adapt to the aquatic environment. Whales are classified as belonging to the kingdom Animal, the phylum Chordata, the class Mammal, and the order Cetacea.

The order Cetacea is further divided into two suborders, namely Mysticeti (baleen whales) and Odontoceti (toothed whales). The division of these two groups is mainly based on their different feeding methods. The main morphological feature of the Mysticeti is that they have no teeth, but have large baleen, which can be used to filter plankton. Therefore, they are filter feeders. The main feature of the Odontoceti is that they have teeth and are predatory. The number and arrangement of their teeth will vary depending on their feeding habits. There are 13 families and about 79 species in the world.

Although the word "whale" has the word "fish" in its name, it is not actually a fish, but a mammal. It has many characteristics that are very different from fish. For example, fish generally move their tail fins left and right to move their bodies forward, while whales move their tail fins up and down. They use the flippers at the front to maintain body balance and control the direction of force. Some whales also have fins on the upper part of their backs to keep their bodies vertical.

Whales are gregarious animals. They usually live in groups in the sea. However, when whales breathe, they need to swim to the surface. At this time, whales use the blowholes on their heads to breathe. When they exhale, the moisture in the air condenses and forms the fountain shape we are familiar with. Experts can even identify the type of whale by the height, width and angle of the water spray. There are many types of whales, which can be roughly divided into two categories: toothed whales and baleen whales.

There is a very thick layer of fat under the skin of whales, which is commonly known as whale oil. It can keep the whale body warm and store energy for emergency use. Because whales have many special structures in their bodies, they can hold their breath and slow down their heart rate in the water for a long time. Therefore, when they sink to the bottom of the sea, they always have to wait for a long time before surfacing. In addition to having a structure to store oxygen, when a certain part of the body needs a large amount of blood supply, there is also a special function in the body to concentrate the supply.

The water column spouted by baleen whales is tall and thin, while the water column spouted by toothed whales is thick and short. Some fishermen can even judge the type of whale based on the water column.

Due to human hunting, at least 5 of the 13 whale species in the world are now endangered. In order to protect whales, the International Whaling Commission has banned commercial whaling since 1986, but the ban was relaxed in 1987 to allow limited whaling "for research purposes." Despite widespread opposition, some countries still kill large numbers of whales every year in the name of scientific research.

Whales come to the surface of the water to breathe every once in a while. Their nostrils are on the top of their heads. When they come to the surface, they spray out a column of water. The water columns of different whales are also different. An experienced person can deduce the type, size and age of a whale by looking at the water column. We also know that whales are not fish.

Other names: sickle-fin dolphin, sickle-fin spotted dolphin, short-beaked dolphin. The snout is very short, but the boundary with the forehead is clear. The dorsal fin is tall and eye-catching, sickle-shaped and curved backwards, with a wide base. The back of the body is black or dark gray, the abdomen is white, the front of the head and the upper jaw are black, and the lower jaw is only black at the tip of the snout, and the rest is white. The body is white or grayish white from the eyes to the ventral side, and there is a white band along the side of the body from the lower side of the dorsal fin to the base of the tail, and from the corner of the mouth to the front base of the fin comb. There is a black band across the rear base of the fin and the entire anus. The front 1/3 of the dorsal fin is black, and the back half is all grayish white. The front edge of the flippers is also black, and the rear edge is gray. The upper and lower parts of the tail fin are black or dark gray. The body color varies greatly. There are 23 to 36 teeth on each side of the upper and lower whiskers.

Adults can reach 2.5 meters in length, with males slightly larger than females, and can weigh up to 180 kilograms. They often live in large groups of dozens to hundreds of individuals, splitting into small groups when feeding and gathering into large groups when resting or moving. They are active, swim fast, and often jump out of the water. They are about 1.8 meters long.

The main food is small schooling fish and squid.

It is distributed in the East China Sea and the South China Sea of ​​my country.

Whales are an important member of marine mammals. They are shaped like fish and are commonly known as whales.

There are many types of whales, more than 80 species in the world, and more than 30 species in my country's waters. They are generally divided into two categories. One type has whiskers but no teeth, called baleen whales, with a total of 11 species; the other type has teeth but no whiskers, called toothed whales, with a total of more than 70 species. The length of whales ranges from 1 meter to more than 30 meters.

Although there are few species of baleen whales, they are all very large. The smallest known species is more than 6 meters in length.

The blue whale can be up to 33 meters long and weigh 190 tons, which is equivalent to the weight of 33 elephants or more than 300 cattle. Its tongue alone weighs 4 tons. It is also extremely powerful, with 1,250 kilowatts, and can tow a 588-kilowatt motorboat. It is the largest animal ever to appear on Earth. This is the blessing of the sea. Only in the sea can it grow so big: first, there is abundant food. Although the blue whale is huge, it feeds on krill that are so small that they are incomparable to it. There are many of these krill, which are easy to catch and can support these big-bellied men. Second, the buoyancy of water is large, which supports the huge body of the blue whale. The African elephant is the largest animal on land, weighing about 5 tons. If the African elephant's weight increases, its limbs will not be able to support it, so it cannot grow too big. But it is not the case in the sea. Animals are basically in a state of weightlessness, so no matter how big they are, they can float. But they cannot grow infinitely. If they exceed a certain limit, the functions of organs such as the heart and lungs will not meet the needs.

The humpback whale's hunting method is very clever. It first shoots a series of bubbles upward from underwater, forming a large circle on the water surface. The bubbles act like an air gun to scare the krill and make them gather in the center of the circle. The humpback whale then floats out of the center of the circle with its mouth open to swallow and eat the krill. Because of the humpback whale's large mouth, it is very efficient in feeding. Each right whale eats 3 to 4 tons of krill every day.

The reason why whales prefer to eat shrimps: In fact, it is baleen whales that prefer to eat shrimps. Because they have no teeth and a small throat, they cannot chew and can only survive by eating small fish and shrimps. When they eat fish and shrimps, they just open their mouths, and the fish and shrimps enter their mouths along with the seawater. Then they close their mouths, and the seawater flows out of their mouths through the gaps between their baleen, leaving only the food.

The whole body of a whale is a treasure. Its skin can be made into leather. Leather shoes, bags, and leather clothes made of whale skin are soft and have beautiful patterns, which are no less than cowhide. The subcutaneous fat layer of a whale is very thick, which can reach tens to dozens of centimeters. It can be refined into oil, eaten, or used as other chemical raw materials.

A blue whale can produce more than 30 tons of oil, which is equivalent to the total amount of fat of 1,700 pigs or 8,000 sheep. The bones and internal organs of whales can be used as medicine or fertilizer. A giant whale can be said to be priceless. Therefore, many countries in the world, such as Japan and Norway, compete to hunt whales, causing many whales to be on the verge of extinction. The International Whaling Commission had to decide to stop commercial whaling.

"Language Masters" in the Whale Kingdom Research shows that killer whales can make 62 different sounds, and different sounds have different meanings. Killer whales living in different sea areas, or even different killer whale groups, use "language tones" that are different to varying degrees, similar to human dialects, so researchers call it "killer whale dialect." Sometimes, a large number of fish appear in a certain sea area, and killer whale groups come from all directions to feed. But their calls are different from each other. Researchers speculate that killer whales can communicate with each other through "language", but as for how they understand each other's "dialects" and whether they have translators like humans, it is still a mystery.

sperm whale

Sperm whales attach great importance to solidarity. If one of their companions is in distress, the group will save the distressed companion regardless of their own risks. Even if they cannot save the distressed companion, they will die with the distressed companion.

[Edit this paragraph] Introduction of whales

The way the Chinese character “鲸” is created clearly indicates that the ancients believed that whales were large fish, not to mention the word “whale”. We cannot blame the creators of the character for lacking common sense in biology, because cetaceans, including whales, dolphins, and porpoises (smaller dolphins), are so similar to fish: their long streamlined bodies, blade-shaped tails, and hind limbs that have shrunk to the point of disappearing, with only a few traces left inside the body, all of which are suitable for life in water.

Scientists believe that mammals appeared on the evolutionary stage at about the same time as dinosaurs, and lived a miserable life in the era when giant reptiles were rampant. It was not until a mass extinction event, usually believed to be an asteroid hitting the earth 65 million years ago, that destroyed the dinosaur family and mammals began to flourish. In the Tertiary Period, 50 to 65 million years ago, all mammals lived on land, and the ancestors of modern whales were no exception. For some reason, some animals that used to run on the land with their limbs began to return to rivers and oceans in the Eocene period 50 million years ago. In less than 8 million years, their body size and living habits have undergone tremendous changes.

These discoveries, especially those of Pakicetidae, are exciting enough for scientists because they are transitional forms between terrestrial mammals and modern cetaceans, again providing beautiful evidence for the theory of evolution. However, these transitional fossils are more inclined to the whale side, either being amphibious or fully adapted to marine life. There are two important questions that remain unanswered: What did the terrestrial ancestors of cetaceans, the most primitive cetaceans that could only run but not swim, look like? Which of the existing mammals in the world is the closest relative to cetaceans?

Scientists are committed to a more detailed understanding of the evolution of whales, and different professionals have different methods. Based on the teeth and ear characteristics of fossils, paleontologists tend to believe that whales are most closely related to mesonychians, an extinct ungulate animal that lived in the Tertiary period. Molecular biologists who study the DNA characteristics of existing animals prefer hippos, believing that this modern even-toed ungulate animal is the closest relative of whales.

On September 20 this year, Thewissen published a report in the British journal Nature, saying that his team had discovered two new ancient whale fossils in Pakistan, which were completely terrestrial. The next day, Gingerich reported in the American journal Science that two other ancient whale fossils were also dug out in Pakistan, with well-developed limbs and could live both on land and in water. (It seems that there are only a few big names in each field, and these two probably have some competitive intentions. It is quite interesting that they published reports on the same topic in two journals of equal status at the same time.) Both of their new discoveries show that even-toed ungulates such as cows, hippos, pigs, camels and giraffes are closely related to whales. For Gingerich, it may have taken a little more effort to put forward this view, because he originally argued that mesonychians are close relatives of whales.

In Greek, the word "whale" means a sea monster. We divide whales into two groups:

Odontocetes: toothed marine giants such as sperm whales, killer whales, dolphins, and porpoises.

Baleen whales: whales with baleen. These baleen are actually angled teeth that grow inside the mouth and replace teeth for filtering water and catching shrimp and other small animals that the whale eats.

As far as all marine mammals are concerned, whales are the most numerous and the largest in number. Whales can be divided into two categories: one is the baleen whales without teeth in their mouths; the other is the toothed whales without baleen but with teeth. Although there are few species of baleen whales, they are huge and have become the main target of human capture. Among them are the blue whales with huge bodies and unparalleled bodies, the right whales with slow movements, big heads and fat bodies, the humpback whales that like to swim near the shore, with short bodies and long arms and funny movements, and the small baleen whales with small bodies and pointed snouts, etc. There are many species of toothed whales. Except for sperm whales, the rest are generally smaller, such as the extremely ferocious killer whales and dolphins. Although the bodies of whales vary in length, thickness, and shape, they are all streamlined and look like fish, so people often call them whales. However, whales are mammals. Like humans, they constantly surface to breathe air. Sometimes we can see white mist columns emitted by whales when they exhale on the sea. Some of them are as high as more than ten meters, like fountains, which is very spectacular.

Whales are mammals that live in water all their lives. They are so dependent on water that they cannot survive once they leave the water. In order to adapt to life in water and reduce resistance, their hind limbs disappeared and their front limbs became paddles for paddling. Their bodies became streamlined, resembling fish. Therefore, they have strong diving ability. Dolphins (small toothed whales) can dive to a depth of 100-300 meters and stay for 4-5 minutes. Fin whales can stay 300-500 meters underwater for 1 hour. The largest toothed whale, sperm whale, can dive to less than 1,000 meters and stay in the water for 2 hours. In 1955, a sperm whale was found dead in the sea near Ecuador, entangled in submarine cables. Its diving depth reached 1,133 meters. A sperm whale was found suffocated by cables at a depth of 2,200 meters in the waters near the Portuguese capital of Lisbon. This is the deepest diving record of mammals so far.

[Edit this section] Ancestors of whales

In the early 21st century, scientists discovered two mammal fossils that lived about 50 million years ago in Pakistan. These two animals look a bit like dogs, only as big as wolves and foxes, but scientists believe that they are the ancestors of the largest animal on earth - whales.

In the early Tertiary period, 50 to 65 million years ago, all mammals lived on land. Therefore, modern aquatic mammals such as whales and dolphins must have evolved from some terrestrial mammals. However, due to the lack of fossil evidence, the question of which type of mammal is the ancestor of whales has remained unresolved. The anatomical morphology of the two newly discovered fossils in Pakistan shows that these two animals lived on land, had carnivorous teeth, and looked a bit like dogs, but did not belong to the canine family. Their tails are longer than dogs, their mouths are more ferocious, and their eyes are smaller. They have several strange bones in the ear area, and their shapes are very similar to the bones unique to the same part of whales.

[Edit this section] [Chinese characters]

whale

[Edit this paragraph] Basic explanation

1879Respondent: 58.55.120.* 2009-9-24 20:58

I will comment>>

Comments from the questioner on the answer: Thank you

Related content

• Urgent! Urgent! Whale's information 83 2009-9-23

• Whale information (to be brief) 135 2009-9-23

• Whale information 367 2009-9-20

• Information about whales 185 2009-2-8

• Is there any information about whales? 20-40 words 2008-11-9

More related questions >>

View the same topic: Information

Other answers: 2

The Latin name of whales is derived from the Greek word for "sea monsters", which shows the awe that the ancients had for these huge creatures that live in the ocean. In fact, the body shapes of whales vary greatly, with small ones only about 1 meter long and the largest ones over 30 meters long. Most of them live in the ocean, and only a few live in freshwater environments. Their body shapes are very similar to those of fish, and they are streamlined and suitable for swimming, so they are commonly called whales, but this similarity is just a convergence phenomenon in biological evolution. Because whales have the characteristics of viviparity, lactation, constant temperature and breathing with lungs, which are completely different from fish, they are mammals. A whale's heart beats only 10 times a minute.

Whale information: Whale information How long does a whale live? How long is the largest whale? Can a killer whale beat a great white shark?

In the 1960s and 1970s, the blue whale was the largest and the killer whale was the most ferocious whale.

General introduction about whales:

Whales are giant creatures in the ocean, and are mammals in the same genus as dolphins (but they are larger than dolphins, with shorter mouths, their forelimbs evolved into flat flippers, their hind limbs degenerated, with flippers, a wide and flat tail, and a blowhole. They belong to the order Cetacea (the suborders Odontoceti, Mysticeti and the extinct Palaeoceti) - Mysticeti and the extinct Palaeoceti. Generally, whales that cannot be classified are classified in the family Delphinidae of the suborder Odontoceti.

They are widely distributed and can be found in almost all oceans around the world. They are ocean-going and often move in groups, rarely acting alone. Like dolphins, they like to play when foraging, such as jumping into the waves, raising their tails, hitting the waves with their tails, and peeping from the water.

Types of whales:

Whales that live in the Southern Ocean are divided into two categories: baleen whales and toothed whales, with about 12 species. The larger baleen whales include blue whales, fin whales, black whales, striped whales, giant whales and right whales; the larger toothed whales include sperm whales and killer whales.

The largest of these is the blue whale, and the most numerous is the fin whale. The great whale and the right whale have now been hunted almost to extinction, with only a few survivors.

Whales are widely distributed in the Southern Ocean, and their traces can be found almost south of the Antarctic Convergence Zone. Their distribution is closely related to the distribution of krill. Blue whales are mainly distributed in the floating ice belt, and the southernmost ones are the giant whales and black whales. The striped whale can overwinter in the Antarctic waters, and the right whale is mainly distributed in the sub-Antarctic region; toothed whales are distributed in the Antarctic Convergence Zone and migrate with the change of seasons.

The life habits of whales:

Fin whales are used to living alone, with both males and females coexisting in the same sea area. Male fin whales can also use their "singing" to attract female fin whales hundreds of kilometers away to come to breeding grounds with abundant food to mate with male fin whales. Since the frequency of whale "singing" is similar to that of some military or commercial sonars, sonars are likely to interfere with the reproduction of fin whales, making the situation of this species, which already has a low reproduction rate, even more difficult.

Narwhals have white bellies and black backs with blue-grey or black-grey spots. They have a 1- to 2-meter-long horn on their heads, which is actually a tooth. Most people now believe that narwhals' tusks are just a secondary sexual characteristic, similar to the mane on the head of a male lion on land. (Habits still to be investigated)

Whales were originally thought to be animals that walked on land with four limbs. Later, due to the problem of finding food, they "went to the sea". Most of them practice monogamy. For example, "humpback whales" usually live alone, while other whales also live in groups. Their gestation period is generally about 12 months, one baby is born, and the baby whales have a nursing period of 10 months. The life span is about 60 to 70 years.

Whales migrate between certain waters in the cold and warm zones, and follow fixed migration routes. They live in the cold zones in the summer, replenish their nutrition, and migrate to warmer waters in the fall for reproduction.

Whales eat mysid shrimp, squid, fish, etc., while killer whales eat penguins, seals, dolphins, whales, etc., and they especially like to eat whale tongues. Wild killer whales are ferocious, but they can be tamed if they are raised from a young age. They have high IQs and can be used for performances.

(Note: Killer whales have a huge appetite. There was a record of one killer whale eating 13 dolphins and 15 seals.)

Reference: Internet