Sea otters have tough skin, can live up to eight minutes without breathing to fetch crabs and shellfish, and generate heat from their muscles to withstand the icy waters of the North Pacific, according to a study released Thursday. Huh.
North America’s smallest marine mammal has a unique mechanism of energy conversion when other mammals warm up their muscles by activating them through exertion or involuntary jerks, according to this study published in the journal Science.
Lead author Trevor Wright of Texas A&M University told AFP that the beaver’s water-resistant fur can limit heat loss, but the water-resistant is not enough to survive in water. Alaskan sea ice, their main habitat.
Scientists already knew that otters, belonging to the beaver family, burn about three times more energy than mammals of the same size, and that they can consume up to 25% of their body mass per day.
But it was not yet known which tissues use this energy and how it is converted into heat.
Mr Wright and his colleagues have taken muscle samples from sea otters that have died or recovered by the Monterey Bay Aquarium, which treats them before releasing them.
Then they measured their oxygen consumption.
– generate heat without doing anything –
In general, animals generate heat by activating their muscles, but in otters, most of the metabolic energy produced by sugars and fats is used to supply heat to the body by their muscles, without causing them to contract.
“They are very good at generating heat without doing anything,” Dr. Wright explained.
This energy would be wasted for land mammals like humans, “but if you’re an animal that wants to be warm, this +wasted + energy is fine” in ice water to maintain a temperature of 37 °C, a T-he says.
This ability is present in otters from birth, whether in the wild or in captivity.
Like other marine mammals, they may have evolved when their ancestors took to the ocean 50 million years ago, but this hypothesis needs to be confirmed with further research.
According to Trevor Wright, knowledge of otter metabolism can also help in curing obesity in humans.
“If we can manage to increase the production (of heat) and basal metabolism, we can theoretically stimulate the human metabolism and make it burn more calories”, even playing sports Even without, he explained.