Reproduction - Baleines En Direct

How do whales do IT?

Although cetaceans live under water, they are mammals all the same. The young develops in the mother’s uterus and is fed directly by the placenta and later, after it is born, by her milk. In short, with a few minor differences, whales do it… just like we do!

Built to purpose

In most species, the only fail-safe way to visually distinguish the sexes is to examine the genital slits. In females, it is located at the base of the belly. This is where the vaginal opening is found, immediately next to the anus. On each side of the slit, there is a fold of skin that conceals a nipple. The male has a genital slit into which the penis is retracted. It is located halfway between the anus and the navel. The reproductive organs are thus hidden inside the body: whales have a streamlined profile that allows them to glide through the water; imagine now the result if the “family jewels” were not so well “tucked away” inside the genital slit…

Courtyard foreplay

Before the two actors take the stage, an intense competition can take place between males of the same species. Sometimes, this competition takes the form of aggressive fighting, as in the case of the humpback whale. For blue whales, males race for a female, a race nicknamed “rumba”. In fact, each ejaculation of a blue whale could produce around 20 litres of sperm. The blue whale’s genital apparatus is proportional to its imposing size, which can reach about 30 metres. The average length of a blue whale’s penis is 2.4 metres. Each testicle weighs between 45 and 68 kg, the same weight as a harbour porpoise.

Another strategy consists of producing the greatest amount of sperm possible to increase the male’s chances of fertilizing his partner. This is what the harbour porpoise does, which is why, during the rut, the male’s testicles reach a combined weight of over 2 kg… Not bad for an animal that tips the scales at less than 60 kg! A man endowed in the same proportion would have testicles weighing over 3 kg.

The female also has her say: if she is not ready to copulate, she might turn her body so as to expose her genital slit out of the water and thus out of reach. The female may also attempt to swim away or might even become outright aggressive toward an overly zealous male who doesn’t meet her criteria.