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Schematic representation of three generations of orcas
Orcas have a complex social organisation (Baird and Whitehead, 2000).
Only seven mammal species (belonging to cetaceans and primates) experience menopause and orcas is one of them (Olesiuk et al., 1990; Wood et al., 2023). Different hypothesis have been made to explain the occurrence of menopause for these species (Van der Bles 2024).
Killer whale populations have the longest recorded post-reproductive lifespan of all non-human animals: females generally stop reproducing in their 30s to 40s but can survive into their 90s (Cant and Johnstone, 2008; Johnstone and Cant, 2010; Olesiuk et al., 1990).
Younger females are favoured and thus have greater reproductive success than older females (their mothers) (Croft et al., 2017).
Ellis et al. (2024) shows that menopause results in females increasing their opportunity for intergenerational help by increasing their lifespan overlap with their grandoffspring and offspring without increasing their reproductive overlap with their daughters (Nattrass et al., 2019). The grandmothers, possessing ecological knowledge can transfer it to the younger generations, favouring their survival (Brent et al., 2015; Foster et al., 2012; Ward et al., 2009; Whitehead, 2015).
Bibliography / Bibliographie
Baird, R. W. and Whitehead, H.: Social organization of mammal-eating killer whales: group stability and dispersal patterns, 2000.
Brent, L. J. N., Franks, D. W., Foster, E. A., Balcomb, K. C., Cant, M. A., and Croft, D. P.: Ecological Knowledge, Leadership, and the Evolution of Menopause in Killer Whales, Current Biology, 25, 746–750, https://doi.org/10.1016/j.cub.2015.01.037, 2015.
Cant, M. A. and Johnstone, R. A.: Reproductive conflict and the separation of reproductive generations in humans, Proc. Natl. Acad. Sci. U.S.A., 105, 5332–5336, https://doi.org/10.1073/pnas.0711911105, 2008.
Croft, D. P., Johnstone, R. A., Ellis, S., Nattrass, S., Franks, D. W., Brent, L. J. N., Mazzi, S., Balcomb, K. C., Ford, J. K. B., and Cant, M. A.: Reproductive Conflict and the Evolution of Menopause in Killer Whales, Current Biology, 27, 298–304, https://doi.org/10.1016/j.cub.2016.12.015, 2017.
Ellis, S., Franks, D. W., Nielsen, M. L. K., Weiss, M. N., and Croft, D. P.: The evolution of menopause in toothed whales, Nature, 627, 579–585, https://doi.org/10.1038/s41586-024-07159-9, 2024.
Foster, E. A., Franks, D. W., Mazzi, S., Darden, S. K., Balcomb, K. C., Ford, J. K. B., and Croft, D. P.: Adaptive Prolonged Postreproductive Life Span in Killer Whales, Science, 337, 1313–1313, https://doi.org/10.1126/science.1224198, 2012.
Johnstone, R. A. and Cant, M. A.: The evolution of menopause in cetaceans and humans: the role of demography, Proc. R. Soc. B., 277, 3765–3771, https://doi.org/10.1098/rspb.2010.0988, 2010.
Nattrass, S., Croft, D. P., Ellis, S., Cant, M. A., Weiss, M. N., Wright, B. M., Stredulinsky, E., Doniol-Valcroze, T., Ford, J. K. B., Balcomb, K. C., and Franks, D. W.: Postreproductive killer whale grandmothers improve the survival of their grandoffspring, Proc. Natl. Acad. Sci. U.S.A., 116, 26669–26673, https://doi.org/10.1073/pnas.1903844116, 2019.
Olesiuk, P. F., Bigg, M. A., and Ellis, G. M.: Life history and population dynamics of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State., Report of the International Whaling Commission, 12, p 209-243, 1990.
Van der Bles, T. J.: Understanding the occurrence of menopause and post reproductive lifespans, Bachelors’ thesis Life Sciences, 2024.
Ward, E. J., Parsons, K., Holmes, E. E., Balcomb, K. C., and Ford, J. K.: The role of menopause and reproductive senescence in a long-lived social mammal, Front Zool, 6, 4, https://doi.org/10.1186/1742-9994-6-4, 2009.
Whitehead, H.: Life History Evolution: What Does a Menopausal Killer Whale Do?, Current Biology, 25, R225–R227, https://doi.org/10.1016/j.cub.2015.02.002, 2015.
Wood, B. M., Negrey, J. D., Brown, J. L., Deschner, T., Thompson, M. E., Gunter, S., Mitani, J. C., Watts, D. P., and Langergraber, K. E.: Demographic and hormonal evidence for menopause in wild chimpanzees, Science, 382, eadd5473, https://doi.org/10.1126/science.add5473, 2023.
April 2025
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