Thermoregulation

From: Phillip J. Clapham (pclapham@whsun1.wh.whoi.edu)
Date: Tue Sep 12 2000 - 19:30:11 EDT


What stops animal cells from freezing in cold water?
That's a great question! It depends a lot on the type of animal. Any
mammals (like whales) are of course warm-blooded and generate body heat
that keeps their body temperature constant. Some fish living in Arctic
waters have a chemical in their blood which is sort of like anti-freeze.
Some other animals that we normally think of as cold-blooded (like giant
bluefin tuna and leatherback turtles) are actually more like warm-blooded;
they have a remarkable system of counter-current exchange which keeps warm
blood circulating.
Whales, of course, are a special case since they're mammals - but we (also
mammals) would die very quickly in some of the temperatures in which whales
live. Their solution to this is blubber - thick layers of fat which
insulate the animal in even Arctic or Antarctic temperatures. In bowhead
whales, which spend most of their lives in the Arctic, the blubber can be
almost two feet thick!

Phil Clapham



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