Eli5: How are humpback whales able to survive in both tropical temperatures and antarctic ones (when my fat can’t protect from either)?

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Eli5: How are humpback whales able to survive in both tropical temperatures and antarctic ones (when my fat can’t protect from either)?

In: 58

First, it a question of economies of scale. You have a relatively small mass compared to your surface area, where the whale has less surface area compared to it’s mass.

Your fat is not as insulating and is different in a few ways, like blubber is more vascularized (has more blood vessels).

Even in tropical waters, whales loose heat. Whales can overheat, and at least one species uses structures in it’s tongue to moderate temperature.

Edit to add, some whales are adapted to live in a fairly wide temperature rage, others are not. Here’s a neat table [Hypothermia Table](https://www.useakayak.org/references/hypothermia_table.html) that shows a person can get hypothermic in seemingly warm ,Over 26.5℃/80℉, water. But on land, where air does not absorb heat as quickly, and where you likely have clothes, you can survive more easily at a wide variety of temps.

I just ran this by my 5yo and they frowned and everything other than whales are big and people are small. And people have clothes, that was important.

You are out in the air, and the air gets very cold. The whales live in the water, and the water doesn’t get nearly as cold. The oceans have currents and huge thermal mass.

Short answer: blubber is very different from human fat.

Long answer: The blubber of sea mammals is highly vascularized (has lots of blood vessels) compared to normal fat and is incredibly thick relative to the body size. It’s also made up of way more lipids than water comparatively. The vascularization allows the animal to regulate its temperature much more easily than a fat human would in tropical waters.

Blubber also almost entirely envelops the body of most sea mammals with the exception of extremities. It’s basically a fat suit surrounding the entire animal, where humans develop fat in deposits unevenly around the body, often times nowhere near the outer skin.

How do whales regulate body temperature between chilling arctic climates, and warm tropic climates?

My only guess is that the ocean waters in the tropics are still relatively cool compared to the outside air, and whales probably dive to deeper depths to cool off.

The most important reason is that whales have a lot more (and better) insulation than even the fattest human. It’s kind of like how the body of a car will not stop assault rifle bullets, but tank armor is practically impervious to them.