Do you know what keeps marine creatures such as seals, whales, and walruses warm in the chilly waters they inhabit? Blubber. It is a thick layer of fat right under the skin of marine mammals, and covers their entire body, except for their fins, flippers, etc. In addition to insulating the animals, it stores energy and increases buoyancy. So one can imagine how integral the blubber is to these mammals existence. But the sea otter, among the smallest of marine mammals, has no blubber at all. And how it stays warm has been a mystery.
Otters are found on all continents, except Australia and Antarctica. They inhabit both freshwater systems such as rivers, lakes, and wetlands, and marine ecosystems. The sea otter is found in the Pacific Ocean. It has been known all along that the sea otter’s thick and water-resistant fur offers it some help with heat loss. But that isn’t enough to protect itself from the cold water of Alaska, where a lot of these otters reside. Scientists also knew “the sea otters burn a lot of energy – approximately three times greater than predicted for mammals of their size, and to keep up with the demand, they may consume up to 25 percent of their body mass in a day”. But what they could not find out was “which tissues were making use of this energy and how it was going towards producing heat”.
And that is what a new paper published in a journal discloses – these creatures have a unique energy conversion system whereby their muscle tissue “leak” large amounts of heat throughout their bodies. Normally, a living creature’s metabolism rate is linked to its activity level. In the case of a sea otter, the metabolism is high but without much activity. So this metabolic energy is being lost as heat rather than being used for powering its muscles. As a news report quotes the lead author of the paper, “they’re really good at making heat by being inefficient. The team behind the study found that this “thermogenesic effect was present in sea otters from the time they were babies to adults.
Apparently, this effect is presumed to be prevalent among animals in the polar regions, but seen for the first time in these marine creatures. The study’s lead author also imagines that understanding this metabolic system could help find solutions to obesity in humans.
Picture Credit : Google
