REPRODUCTION

Cetaceans use a large variety of reproduction and courtship strategies. Generally, courtship depends on the distribution of females, which ultimately are dependent on their habitat or surroundings. In this way, courtship has become a competition between males, in which the most capable produce a large number of offspring.

Normally females invest more time into care of offspring than males. Due to this, males don’t waste time or effort into bringing up young, so can dedicate more time and effort towards courtship. This has resulted in polygyny becoming the commonest reproductive strategy for marine mammals. Monogamy has been unheard of to date.

Some strategies of male dolphins and whales include visual or accoustic displays to attract females. The best known case is that of the humpback whale, in which the male creates a complex song to attract females. See details.

Like many other large mammals, cetaceans generally produce one offspring at a time, which they care for over a long period. Gestation is relatively long, varying from 8 – 16 months ( sperm whale) depending on the species. Lactation also varies greatly, from several days to several years. This length of lactation is common for species with high levels of social cohesion like orcas or sperm whales.

Cetaceans reach sexual maturity in several years, although this varies between species. For example the humpback whale matures in 4 years, while the bowhead does not mature until at least 15 – 20 years. This is because in polygynous species, males do not mature until they are able to compete with other males.