![]() Blood flowing to the flippers is cooled down by blood returning to the body and enters the flippers at a lower temperature. There are blood vessels just under the skin in the webbed area, between the toes of the flippers. They also use their flippers to regulate the body temperature. When it gets very cold, seals can pinch off the blood flow to their skin in order to preserve the heat. Only the flippers and head are without blubber. Sometimes the layer is more than 5 centimeters thick. Most parts of the seal are well insulated with a thick layer of blubber. There are known incidents where seals stay under water up to half an hour, however on the average, their stay is not longer than fifteen minutes. Because they are sleeping and not actively swimming, they can stay under water much longer than when hunting for food. In the water, they sleep floating in a standing position, like a fishing bobber, or floating horizontally on the surface. Seals sleep in the water as well as on land. Sea lions, on the contrary, can use their back fins more or less as ‘hind feet’. That is why they can walk much better than seals. Seals drag their body over the ground with the help of their front flippers, a movement referred to as hobbling. They can’t walk since their hind fins lie in extension of their body. All these adaptations have made them very clumsy on land. In the course of millions of years, they have adapted in all kinds of ways to life in the sea. But that is hard to notice nowadays when you see a seal on land. Once above water, the heart beat of a seal increases to 120 beats per minute in order to provide enough oxygen for the organs. When they ascend from deep depths, they can pump out the inhaled air from the air sacs, preventing deadly nitrogen bubbles from entering the bloodstream. This means they don’t need to breathe as often. Furthermore, they can lower their heart rate tremendously during the dive, from 40 to less than 1 beat per minute. Their blood can absorb much more oxygen than human blood. During the first few minutes, they swim actively downwards, after which they go into a kind of gliding flight while they sink even deeper. Their body is totally adapted to long and deep dives. Seals can dive down to depths of hundreds of meters. But eventually, most of them learn it on time.Ī seal swims just as readily on its back as on its belly, standing upright or upside down. The front flippers serve as paddles the body and hind fins provide the propulsion. In this period, young seals lose a lot of weight. Their mother doesn’t teach them the tricks. Young seals must teach themselves to eat and catch fish after nursing ends. Flatfish, lesser sandeel and cod species are their favorite food, although what they eat can vary per season, depending upon what’s available. Seals do not have a preference for one specific fish species, but they usually catch fish that live close to the sea bottom. They can also determine the size and shape of the fish from a distance. In that way, seal can ‘see’ in turbulent water where the fish are, up to a distance of 100 meters. Seals can feel the slightest movements in the water. They use their whiskers for locating prey in these predominantly turbid waters. They like to lie in the sun while resting on a sandbar or beach. Nevertheless, you can spot them regularly on the surface. Seals are completely adapted to life under water. However, they would need eyeglasses to see sharply above water. ![]() With its cute, round eyes, seals see very well under water. ![]() A seal easily races through the water at 35 kilometers per hour, while it is lucky to cover 2 kilometers per hour on land. Seals are the acrobats of the sea, but they are very clumsy on land.
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