Animals with antifreeze

Animals with antifreeze

Why don’t fish freeze in the Arctic Ocean?

Brrrrr! It's cold outside. Lots of animals are much better adapted to the cold weather than we are. Polar bears have thick fur, seals and whales have a layer of blubber and some birds migrate.

But what if you're a fish?

Birds and mammals are 'warm-blooded'. They can keep their body temperature higher than the icy environment around them. Fish are 'cold-blooded'. Their body temperature is the same as their surroundings. In the Arctic and Antarctic Oceans, the temperature is very chilly - below 0 degrees Celsius. The salt in the oceans stops them freezing.

Why don't fish freeze?

To stop their blood freezing, some fish that live in the Arctic and Antarctic have special antifreeze proteins.

Antifreeze proteins are very clever. They slow down the formation of bonds between water molecules, which prevents the formation of ice crystals in the fish's blood.

Scientists are working out how they could use these antifreeze proteins as a non-polluting de-icer for cars and machinery. Antifreeze proteins could also be used to prevent food freezing and to preserve delicate organs during organ transplants.

To find out more about how antifreeze proteins work, go to Neutrons and antifreeze: research into Arctic fish.


Curriculum information

  • Summary


    Curriculum key wordsOther web links
    • 5
    Science Curriculum Links
    National CurriculumCurriculum for excellenceNorthern Ireland Curriculum