Sea otters are pretty small compared to other marine mammals (哺乳动物), which means that, despite their fur coats, they tend to lose heat quickly, and need lots of energy to keep up their body temperature.rn“So they need to eat 25 percent of their body weight each day,”says Sarah McKay Strobel, a sensory ecologist at UC Santa Cruz.“But in order to eat that much food, it means sea otters need to find all that food.”She studied the otters' senses, to solve the mystery of how they're such efficient food catchers. Vision isn't reliable, she says—it's pretty dark and muddy underwater, and crabs and other smaller animals tend to hide. Hearing is also tough for otters in the noisy underwater environment. And sniffing's no good either.“When they're underwater, they're holding their breath.”