2021 July 9th Friday
Keep warm without the fat layer
Researchers solve mysteries about sea otters
How do sea otters manage to avoid freezing in cold Pacific waters? Experts feel in the dark when it comes to this question. This is because animals do not have enough fat layer by layer. A new study finds something surprising: the mammalian system is very unique and actually very inefficient.
Researchers have discovered how sea otters bravely manage the freezing temperatures of their habitat in the North Pacific. Marine mammals use their muscles to generate heat instead of moving, according to a study published in the journal Science. For example, unlike seals and whales, they are available in cold water without dense layers of fat.
Sea otters have a lush, water-repellent fur. However, this alone is not enough to compensate for the heat loss caused by cold water, said Drew Wright, an otter expert at A&M University in Texas. How warm the animals are has long been a mystery.
Sea otters are known to use more energy – three times their size for mammals. In severe cases, animals burn up to 25 percent of their body in a single day. Wright and his team now focused on the question of how and for what purpose this energy is used.
They took muscle samples from dead seafarers and examined live animals from the Monterey Bay fishery. Usually the main function of the muscles is to move the body. In otters, however, most of the metabolic energy is lost to heat instead of work such as muscle contraction.
“One interesting thing we found is that they are very good at generating heat by being inefficient,” Wright explains. To terrestrial mammals like humans, this may seem like a waste, “but if you’re a hot-tempered animal, this wasted energy and warmth is a good thing.”