Five Fact Friday: Antarctic Animal Survivors

1. The largest animal to survive year round on the Antarctic continent is as wingless midge, named Belgica antarctica, that is 2-6 millimetres long.
2. The largest whale in the world also frequents Antarctic waters where it feeds mainly on krill. It is amazing to think that a 150-200 tonne animal survives on such tiny creatures.
3. The fish that live in Antarctic waters have adapted over time to survive such cold. One group of fish - the ice fish - have no haemoglobin at all and are the only vertebrates to do so. The reason it can survive with no haemoglobin - which serves in other animals to transport oxygen throughout the body - is that the well stirred Antarctic waters are oxygen rich and the cold slows the metabolism down to such an extent that the ice fish have a metabolic rate of half that of other Antarctic fish. They also have very large blood vessels and a massive heart.
4. The majority of fish in Antarctic waters have also developed their own antifreeze, which resides in their blood. This is a mixture of sugars and proteins which interacts with the faces of the ice crystals and hinders the addition of more water molecules to the crystals - thereby preventing the growth of ice within the fish.
5. Birds are also present at various times of year on or around Antarctica. The wandering albatross is one such example. The most famous bird of Antarctica must be the Emperor penguin. The males look at the egg in a special pouch above their feet throughout the Antarctic winter. Along with their biological adaptations, they also huddle together to keep warm during this time.

References
Fothergill, A. (1993) Life in the Freezer, London, BBC Books.
http://en.wikipedia.org/wiki/Belgica_antarctica