Cetacean life cycles: gestation, weaning, longevity

From birth to prime

Cetaceans are champions of animal longevity. A bowhead whale can live 200 years, a female killer whale 80-90 years. But that longevity comes with a very slow reproductive strategy: long gestations (10-17 months), prolonged lactation (sometimes up to 8 years in some killer whales), late sexual maturity. Comparative table for 25 species.

Going further

The life cycle connects with other biological dimensions: lactation in detail, mating systems, social cohesion and population demographics.

Longevity, menopause, alloparental care

Cetaceans have long and complex life cycles. The bowhead whale (Balaena mysticetus) holds the mammalian longevity record: a stone harpoon found in 2007 in one individual allowed its age to be estimated at more than 200 years (George et al. 1999, dating by amino acid racemisation of the eye lens).

Female killer whales and pilot whales go through a true menopause, a trait that is extremely rare among mammals. According to the “grandmother hypothesis” (Croft, Cant), old non-reproductive females pass their ecological experience on to their grandcalves, which increases the fitness of the group. Alloparental care, caring for the calves of other individuals, is attested in many social species, in particular the sperm whale and the common bottlenose dolphin.