Otterly Cozy

Which marine mammal is not like the OTTERS?

This is Sandra Tsing Loh with the Loh Down on Science.

Swimming in the Pacific can be…CHILLY! Larger ocean mammals like walruses and whales have a secret weapon–blubber! But how does a small otter stay cozy while frolicking adorably in the sea? 

Traver Wright from Texas A&M University and colleagues wondered. They studied leg muscles of wild and captive sea otters from pups to adults. Using a respirometer, they measured how much oxygen was needed for the leg cells to work properly.   

Results? Although their fur helps keep them warm, the answer is in the otter’s MITOCHONDRIA! Those are the energy factories of a cell. These little generators release heat by leaking electric charges into the muscle. Think – drippy kitchen faucet! 

BUT sea otter mitochondria leak out at a higher rate than other marine mammals! This keeps them nice and toasty as they plunge into the ocean. 

And makes them the smallest members of the Polar Bear Club! These furry friends stay warm one way or an OTTER! 

Reference: Wright, T., Davis, R. W., Pearson, H. C., Murray, M., & Sheffield-Moore, M. (2021). Skeletal muscle thermogenesis enables aquatic life in the smallest marine mammal. Science, 373(6551), 223–225.