Seal, you can swim. Why are you always pulled out of the water？

Original Maya Blue Species Calendar

Did everyone watch the recent super-hot animation Sealook (also called "Leopard Watch")? The protagonists in the animation are all Q-bomb leopards, but as a nature lover, I can’t help but notice many details in the animation.

For example, the occasional round hole in the ice.

Seals and ice caves | Sealook

Such ice caves often appear in expression packs, from which a fresh leopard can be found (not).

Much like me who doesn’t want to go to work.

These ice caves are seals’ life-saving passages: breathing holes.

Seals are masters of diving and fishing, but as mammals, they still have to come back to the surface for air often, or they will drown. It is of course feasible to breathe in the cracks of the sea surface or ice layer, but if there are large stretches of sea ice above, they can only rely on breathing holes.

Weddell seal resting in the breathing hole looks super comfortable | ｜Youtube

The Antarctic seal (Leptonychotes weddellii) likes to snorkel under the solid ice for a long time. It is said that when they rest on the ice, they usually don’t leave the breathing hole for more than three meters. For seals, the breathing hole is the door of their lives.

Learning to find breathing holes is more important than learning to hunt.

Weddell seal cubs are going to swim in the cold sea two weeks after birth. At this time, the first thing they have to learn is to find breathing holes, which is even more important than eating.

In a study published in 2021, scientists compared the behavior patterns of young seals and adult seals in the sea, and thought that young seals and adult seals would practice navigation and positioning under the ice and find breathing holes when swimming in the water. They are not sure about the role of mother seal in this process, but it is likely to be a teaching behavior.

Between learning to swim, Weddell seal cubs and their mothers rest at the breathing hole | Linnea Pearson

Adult Weddell seals can hold their breath for up to 1.5 hours, ranking among the best in the seal family, but young ones rarely dive for more than ten minutes. Drowning due to lack of swimming ability or inability to find breathing holes is one of the main causes of death for Weddell seal cubs.

What’s the saying? People who drown can swim …

You can’t dig an ice hole without a good mouth.

Adult Weddell seals have another responsibility, which is to maintain and defend the breathing hole.

When the temperature drops and the ice cave shrinks due to freezing, seals have to soak in the cold sea water and rub their jagged front teeth and canine teeth to widen the hole.

Seal shaved ice | ｜Youtube

When people with sensitive gums see this picture, it is estimated that it has already started to hurt. In fact, the seal’s teeth can’t stand such a toss.

When they are about twenty years old, they will be unable to hunt and repair ice caves because of their worn teeth, and then they will die. Jerry Coyne, an American biologist, wrote in his blog: "If evolution can create perfect adaptability, it should make seals have growing teeth, just like rodents!

Weddell seal’s skull shows that the incisors and canines (arrows) have worn into the pulp cavity, and there are two abscesses in the maxillary bone (the right canines have been removed to determine their age) | B. M. Dukes

Perhaps the evolution king is more kind to the ring seal (Pusa hispida). Ring seals dig breathing holes with their front paws, which sounds much more reasonable than gnawing with their teeth. It will also be more labor-saving to choose cracks and weak spots on the ice to start construction.

Breathing hole is not only a vent hole for seals, but also an entrance for fishing. For seals living in the Arctic, breathing holes can also help them escape quickly when polar bears appear. But polar bears will also guard the ice cave and wait for the unlucky seal.

Although I really want to find more videos of Arctic seals digging breathing holes to share with you, Weddell seals have been studied the most. On the one hand, the behavior of different seals is different, and on the other hand, the activity area of Weddell seal is close to the Antarctic scientific research station, so it is convenient to study.

There are still many unknown secrets hidden in polar animals, but climate change is threatening their lives. Seals not only rely on the ice to inhabit and reproduce, but some of them also dig holes in the ice to raise their offspring. Climate change will lead to drastic changes in their habitat environment and affect their food sources.

Fight climate change and don’t let glaciers melt into the ocean. Leopard is good, and people are good.

references

[1]https://academic.oup.com/jmammal/article/102/4/1000/6290999? login=false#285787621

[2]https://www.eurekalert.org/news-releases/824652

[3]https://whyevolutionistrue.com/2019/08/14/weddell-seal-chews-breathing-hole-in-the-ice/

[4]https://www.fisheries.noaa.gov/species/ringed-seal

Author: Maya Lan

Original title: "Seals, you can swim, why are you always pulled out of the water?" 》

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