A baby whale is referred to as a calf from the time of its birth until it has been weaned. Thereafter, it is often referred to as a juvenile cow or bull, based on its gender. Depending on the species of whale, the gestation period can be anywhere between 10 and 18 months long.
The calf is born live (as opposed to an egg that hatches, as is the case with sharks, for example), alert and able to swim to some degree. It may be born head-first or tail-first, and is born directly into the ocean water. Due to its being an air-breathing mammal, the calf needs to take its first breath of fresh air shortly after its birth.
Therefore, it is a priority to the mother to raise it to the surface of the water, exposing its blowhole (on the top of its head) to the outside air. If the mother is too exhausted after the birth, the midwives (other cows in the mother’s pod) will perform this important duty. Within a few hours of the birth, the calf will begin to nurse. There are mammary glands that are concealed within slits on the mother’s abdomen. The calf will nuzzle her until it locates these and will then suckle on the milk, which has a very high fat content. This fat is necessary to allow the baby to gain weight and strength so that it may form its own layer of blubber, which insulates it and provides it with energy.
The calf will nurse for anything between six and 24 months, depending on the species of whale to which it belongs. Some species will even continue beyond two years of age, and after the mother has ceased to lactate as a sort of comfort and bond with the cow.
In general, a calf is about one-quarter the size of its adult counterparts at birth. However, thanks to the rich milk, it grows and develops quickly, and will soon reach a far larger size. They are also usually duller in colour, without the very distinctive markings of its parents and adult peers. This serves as a protection, as they are not as clearly spotted in the water by potential predators.
The calf is protected and taught by its mother as well as by the other cows in the pod. The matriarchal structure of the whale society makes for a social life for the youngsters, one that is supported by an array of “mothers”. The bulls are not part of the weaning or training of their calves. Rather, they live an independent life in bachelor pods, leaving the rearing of the calves to the mothers.
Once the calf has been weaned and, if necessary, taught to hunt, it is able to move on from its parental pod. Juvenile males will frequently join bachelor pods of other young bulls, although they are not yet ready to mate. Young cows will likely stick to their mother’s pod for quite some time. They may move to another pod when they are older but are also known simply to join the pod in which they were raised.