Why Do Whales Get So Big? Science May Have an Answer.

[Judi Lynn]

Marine mammals have evolved their whopping size for a reason—and it's not what we expected.



By Carrie Arnold
PUBLISHED MARCH 26, 2018

Land mammals can get plenty big, but to find the planet’s true giants, you'll have to take to the seas.

In a new study, scientists show why that is. Marine mammals "have to find a happy medium between getting enough food and producing enough body heat," says study leader William Gearty, an ecologist at Stanford University. (Read about a bus-size whale that's still a mystery to scientists.)

Previously, researchers believed that marine mammals could be so large because the buoyancy of water frees them from the constraints of gravity. Although this freedom may still be a factor, Gearty says that his results show that marine mammals need their heft to keep themselves warm in the often chilly oceans.

"These animals are big for very specific reasons. It’s not that they could be big, it’s that they must be big," he says.

More:
https://news.nationalgeographic.com/2018/03/whales-size-animals-ocean-marine-mammals/

[Judi Lynn]

1. Why Aren't There Any Supersize Whales?

By Laura Geggel, Senior Writer | March 26, 2018 06:11pm ET

Whales are giant beasts, but why aren't even larger, supersize whales swimming around?

The answer has to do with food, according to a new study that found that it would be basically impossible for an ocean-bound creature to eat enough food to support a body bigger than a whale.

"At a certain point, you just can't eat enough food, no matter how much there is, to sustain the largest sizes," study lead research Will Gearty, a doctoral student in geological sciences at Stanford University, told Live Science. [Whale Album: Giants of the Deep]

Gearty and his colleagues were looking at how body size changed as land mammals evolved into water creatures. This didn't just happen to whales and dolphins, which are related to hippos and other hoofed animals, but also to seals and sea lions, which are relatives of dogs, and to manatees, which share ancestry with elephants, the researchers said.

More:
https://www.livescience.com/62127-why-are-whales-so-big.html