Weddell Seal (Leptonychotes wedelli) pup with mother

Weddell seal milk is one of the richest produced by any mammal. It contains about 60% fat (go and compare that to the label on the milk carton in the fridge) and it is this that is responsible for the rapid weight gain made by pups shortly after birth. They are weaned (stop drinking milk and begin eating normal seal food, i.e. fish) at around 7 weeks when they should have reached about 110kg (242lb). When adult, they will weigh up to 400kg (880lb) and be up to 3m (10ft) long. Unusually, the males are slightly smaller than the females.

Pups are encouraged into the water very early on by their mothers, perhaps only a week or so after birth. The water is their natural habitat and with their thick protection of blubber is a more comfortable place to be most of the time for these seals than out on the ice where the temperature can be -40° C or less with winds frequently of gale force or greater.