Page 78 - KBHA BULLETIN 4

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Calves consume about 600 litres of milk daily. They are fed for about 6 to 8 months by the cow

and grow 2,8 cm per day. Three percent of Southern Right calves are born white and they will
become brindled when they become adults.

The calves are very lively and can often be seen breeching over and over again. They throw

themselves right out of the water landing on their backs. This is thought to be a sign of
communication and also to get rid of old skin and some of the whale lice mentioned earlier.

Southern Rights calve every three years from the age of about 7 years. At the moment our

population is growing at 7% per year.

Towards the end of September you will notice that there are many more whales in the bay. This

is because the males have come to join the females for the mating season. The cows mate with
more than one bull. This is called sperm competition. Each male dilutes the sperm of the male

before him and you will then find that the dominant whale, whose testes weigh in the region of
one ton, will then have sufficient sperm to blow out all the sperm from the other whales. It is

believed that the first cows to leave the bays are the ones that have conceived, as they will have
to get back to Antarctica and be there when the krill swarms up from under the ice.

The departure of the cows with calves will depend on how well the calves have grown as this
will determine their safe arrival in Antarctica.

Krill lives under the ice for the winter period as a juvenile, in the summer period they mature,

and as adults they swarm up from underneath the ice. Their swarming behaviour is not well
understood but krill are very unusual in several ways. They are heavier than water so they must

keep moving in order to avoid sinking. They hang in the water at an angle of about 55 degrees,

constantly paddling with their ten legs. 40% of their energy is used in just maintaining their
position in the water. If they don't find enough food, or if they are simply weak individuals, they

sink towards the bottom where they will suffocate due to a lack of oxygen.

It is thought that the total weight of krill in the world’s oceans weighs more than the whole

human race. Humans are harvesting krill from the oceans; the Russians use theirs for animal

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