Study
Reproductive conflict and the evolution of menopause in killer whales
Croft, Darren P.; Johnstone, Rufus A.; Ellis, Samuel; Nattrass, Stuart; Cant, Michael A.
Current Biology, 2017
Decades of individual-level demographic records from resident killer whale populations were analysed to compare calf survival when older and younger females bred at the same time, and to test predictions about relatedness changing over a female’s life.
- Studied in
- Orcinus orca
- Sample size
- individually identified whales in a multi-decade demographic record
When an older female and her daughter bred simultaneously, the older female’s calves were substantially more likely to die. A female’s relatedness to her group rises as she ages, which makes continued breeding costlier than helping.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Reproductive conflict between generations, combined with increasing local relatedness, explains why killer whale females stop breeding decades before they die.
How NatureHQ reads it
Menopause is vanishingly rare — humans, killer whales and a handful of other toothed whales — so an explanation that works here is interesting well beyond killer whales. The strength of the result is that it makes a quantitative prediction about *which* calves die and the demographic record bears it out. It does not show that older females intend to help, and it is a statistical pattern across decades rather than an observed decision.
- Observational demography; no experimental manipulation is possible.
- Confined to well-studied resident populations in the North Pacific.
- Alternative contributions such as ecological knowledge are complementary rather than excluded.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Cell PressPublished in a Cell Press journal.
doi.org/10.1016/j.cub.2016.12.015
This reference was resolved automatically against Crossref and OpenAlex on 2026-08-11.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-09.