Sea otters are one of the smallest marine mammals, reaching about 1.2-1.5m in length and 14-45kg in weight. And unlike other larger mammals, such as whales, who depend on fatty blubber to maintain heat, these smaller animals are unable to do so since they lack the same fatty blubber. So, how exactly are they staying warm in cold temperatures? This has made researchers curious for years. Well, now, they have finally found an answer to this decades-long mystery. Here's what they uncovered.
Although sea otters do have a thick layer of fur, it isn't adequate enough to contain the needed core body temperature. They usually have a stable core temperature of 37 degrees. But they do live in water, which tends to drop -1 degrees. The way they increase their body temperature is actually through their muscles. Essentially, sea otters contain heat within their body by manipulating the biochemistry of their muscle cells.
When living cells create a chemical reaction, it is called metabolism. Sea otters count on full muscle metabolism, which controls the entire metabolism of the body, to retain body temperatures. So how does it work? When a body is given food, it turns the eaten carbs, fats, and proteins into chemical energy, which in turn helps provide energy for the necessary activity in one's body. The food gets broken down into its basic constructs and then transported throughout the body's cells. In the mitochondria, they are oxidized into ATP, the energy source used by cells.
The energy released from the food molecules is what helps pump charged hydrogen (H) and atoms (H ions) from the inner mitochondrial into the space between the inner and outer mitochondrial. As it crosses the membrane, the H ions produce ATP. But if the H ions do not spin the molecule wheel as they cross through the membrane, then no ATP is made, and the energy built up in H ions is let go as heat. To maintain this high metabolism, sea otters are required to consume at least 25% of their body mass in food each day. This is how sea otters are able to withstand colder temperatures, as found by Traver Wright and colleagues.