CATDOLL : CATDOLL: Why are many animals afraid of sea urchins? Why are many marine animals afraid of sea urchins?

Why are many animals afraid of sea urchins? Why are many marine animals afraid of sea urchins?

Animals are afraid of sea urchins because they have a hard shell and are covered with sharp spines with barbs at the front end. They can inject venom into other animals after stinging them, which can cause redness and swelling at the mildest and whole body convulsions at the worst.

Who has information about sea otter?

Sea otter (Enhydra lutris; sea otter)

Classification: Carnivora, Mustelidae, Enhydra

introduce

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Sea otters are rare animals that are only found in the cold waters of the North Pacific. Sea otters have the densest hair in the animal kingdom (one million hairs per square inch). According to zoologists, sea otters evolved from otters that lived in rivers and moved to the seaside about five million years ago and became sea beasts. Therefore, sea otters are not as good at diving as their predecessors, sea seals, who have lived in the sea for 35 million years, and they also lack a thick layer of subcutaneous fat to resist the cold.

The sea otter's ability to resist cold comes from two genetic mutations, internal and external. The external mutation is the growth of dense hair mentioned above, while the internal mutation is the consumption of large amounts of seafood to produce heat energy.

Therefore, sea otters are not only the best fur-bearing animals in the animal kingdom, but also the animals with the largest appetite on earth, usually consuming seafood equivalent to one-third of their body weight in a day. In other words, a mature sea otter weighs about 60 to 70 pounds, so on average, each one eats more than 10 pounds or even 20 pounds of seafood a day.

feature

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Sea otters are the only marine animals among carnivores. Adult male sea otters are 1.47 meters long and weigh 45 kilograms. Female sea otters are petite, about 1.39 meters long and weigh about 33 kilograms. The tail of a sea otter is about 30 to 40 centimeters long. It has a small head and a fat body. Its forelimbs are short and exposed, and its hind limbs are long and flat. There are webbed feet between its toes, which are fin-shaped and suitable for swimming and diving. Sea otters mainly live in the sea, and only come ashore to rest and give birth. They even float in the sea when they sleep. Sea otters are marine animals that use tools to hunt. Sea otters have a thick layer of body hair. Its fur is the densest among mammals. As early as 260 years ago, people discovered that the fur of sea otters was a precious thing to keep out the cold, so they hunted them in large numbers. In Alaska, it is said that a Russian captured tens of thousands of sea otters at a time, took the skin and meat, and sold them at high prices to make huge profits. By 1911, the number of sea otters was only 1,000. Later, after protection, the number of sea otters recovered.

Sea otters are good at diving, often diving to 3 to 10 meters, and sometimes diving to 50 meters deep to find food. They rarely move on land and never go far from the coast. At night, they can sleep on the sea surface. Compared with other sea animals, sea otters swim relatively slowly, only 10 to 15 kilometers per hour.

Sea otters eat mostly shellfish, abalone, sea urchins, crabs, etc. that grow on the seabed. Sometimes they also eat some seaweed and fish. Their favorite food is sea urchins, but the shells of sea urchins are very hard and cannot be opened by teeth. Sea otters have come up with a very clever way: pick up sea urchins underwater and clamp them in the loose skin under their forelimbs, then quickly float to the surface, swim on their backs with their four legs facing upwards, put a fist-sized stone picked up from the seabed in front of their chest as anvil, and use their forelimbs to clamp the sea urchins and hit the stones. Once they find that the shell is broken, the sea otters will immediately suck out the meat inside. After eating, they will save the stones and use them repeatedly. In this respect, sea otters are better than apes.

The most valuable part of a sea otter is its fur. Clothes made of sea otter fur are the best for keeping out the cold. Seawater transfers heat four times faster than air, and sea otters do not have a thick layer of subcutaneous fat like whales to keep warm. Its subcutaneous fat accounts for only 1.8% of its body weight, but sea otters have thick fur, with 125,000 hairs per square centimeter, and a layer of fat on the fur, which makes it impervious to water even in deep water.

detailed

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Sea otters are mammals that live in the Aleutian Islands and the coast of the Kamchatka Peninsula in the Pacific Ocean. They are good at swimming and diving. They are about 1 meter long and have a tail of about 30 centimeters. They only come on land when they rest and breed. They have short forelimbs, which are used for feeding and combing their fur. Their hind limbs are long, wide and flat, fin-shaped, with webbed toes, which can paddle like an oar. Their long tail acts like a rudder to control the direction when moving forward.

For a long time, people always thought that they were the only intelligent animals that could use tools. However, the facts show that other animals can also use tools. Sea otters like to eat hard-shelled animals, such as sea urchins, mussels, clams, etc. These animals have very hard shells, and the teeth of sea otters cannot bite them at all. So how do sea otters break the shells to eat meat? Smart sea otters thought of harder stones. After they catch sea urchins or other mollusks on the seabed, they first hide the prey in the leather bags under their two front legs, swim to the surface and lie on their backs, put the square stone about the size of a fist that they carry with them on their chests as a cutting board, and then use their front legs to grab the prey and hit it hard against the stone. After hitting it a few times, check whether the shell of the prey is broken. If it is not broken, continue to hit it hard until the shell cracks and the meat is exposed. Some people have calculated that a sea otter can catch 54 mussels from the seabed in one and a half hours and hit the stone 2237 times. After eating, sea otters hide stones and leftover food in their skins so that they will not be lost even if hit by waves, so that they can be used again.

The sleeping pattern of sea otters is very interesting. When night falls, some sea otters also climb ashore and sleep on rocks, but most of the time sea otters sleep on the sea surface. They look for places where seaweed grows, roll over and over, wrap the seaweed around their bodies, or grab the seaweed with their limbs, and then sleep with their heads on the waves, so as to avoid the danger of being washed away by big waves or sinking to the bottom of the sea while sleeping. This sleeping pattern of sea otters can effectively resist the threat of enemies coming from the shore. When sea otters are sleeping, if they are attacked by enemies or frightened, most members will immediately dive and escape, but a few members often stay to find out the cause of the disturbance. Once they find that there is indeed danger, they will use their tails to "papapapapa" to hit the water surface as an alarm signal to notify other members to escape quickly. In addition, sea otters have a particularly sensitive sense of smell and can smell the smell of people's breath 8 kilometers away. If someone walks on the beach, they will not go ashore unless the smell left by the person is washed away by several tides. This sensitive sense of smell helps them detect enemies early.

Sea otters love to "dress up". In addition to foraging and resting, they spend a lot of time grooming and licking themselves, including their fur, head, tail, and limbs. They even clean their chest and abdomen, which is their "dining table". This kind of "dressing up" is for their own survival. Sea otters rely on their fur for protection. If their fur is unkempt or dirty, seawater will directly penetrate their skin, dissipating their body heat and causing them to freeze to death.

Sea otters reproduce slowly, with one litter every five years, usually only one baby. Twins and triplets are extremely rare. The pregnancy period for sea otters is as long as one year. Newborn sea otters are almost defenseless in the first year. No matter where their mothers go, they can only hang on their chests. According to statistics, only one out of every 10 baby sea otters will be able to expand their territory in the future. Coupled with the large-scale hunting of sea otters by humans for their precious fur, sea otters were on the verge of extinction in the past. Now that their conservation activities are taken seriously, the number of sea otters has increased to tens of thousands.

Strange way of eating

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Sea otters like to eat sea clams, sea urchins, chitons, abalone, shellfish and other animals with hard shells. So how do they eat the meat inside the hard shells? It's very interesting. They dive to the bottom of the water, pick up a few shellfish or sea urchins, stuff them into the folds of their stomachs, pick up a stone, swim to the surface, float on their backs, put the stone on their stomachs, and then use their forelimbs to repeatedly hit the seashells against the stone until the hard shells break, so that they can eat the meat inside.

High level of vigilance

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Sea otters forage during the day and sleep at night, but they do not sleep on the shore, but in the sea where seaweed grows luxuriantly, wrapping their bodies with seaweed to prevent being washed away by the waves after falling asleep. Sea otters sleep very close to each other. When a large group of sea otters fall asleep, there are always a few sea otters standing guard around. Once the sea otters on duty discover something, they will make a loud scream to wake up the sleeping sea otters.

Sea otters sleep in an interesting way. Most of the time, they sleep on the sea surface. They look for places with dense seaweed, roll over and over, wrap the seaweed around their bodies, and sleep with their heads on the waves. This sleeping method can protect against the threat of enemies.