Too big…? too small… ? This BODY size is just right!
This is Sandra Tsing Loh with the Loh Down on Science.
Mammals that live in the ocean are some of the largest animals in the world. Think whales and walruses. These mammals’ ancestors used to live on land. When they evolved to live in water, their average mass grew to over one thousand pounds!
So why does the life aquatic make creatures balloon in size compared to land mammals? William Gearty and others at Stanford University wondered.
They studied almost seven thousand living and extinct mammals, and built a phylogenetic tree. Like a family tree of evolution. They also studied the animals’ food intake and metabolism. With all this information they predicted HOW and WHY body sizes have changed over time.
Turns out marine mammals grew massive to maintain their body temperature! Bodies lose heat much faster when under water compared to out in the air. Some animals might use blubber or thick fur to fight the heat loss. But the BEST way to keep warm? Just keep growing!
Whale, I think I OTTER go put on a jacket!