The evolution of menopause in toothed whales.

Nature

Centre for Research in Animal Behaviour, Department of Psychology, University of Exeter, Exeter, UK.

Published: March 2024

Understanding how and why menopause has evolved is a long-standing challenge across disciplines. Females can typically maximize their reproductive success by reproducing for the whole of their adult life. In humans, however, women cease reproduction several decades before the end of their natural lifespan. Although progress has been made in understanding the adaptive value of menopause in humans, the generality of these findings remains unclear. Toothed whales are the only mammal taxon in which menopause has evolved several times, providing a unique opportunity to test the theories of how and why menopause evolves in a comparative context. Here, we assemble and analyse a comparative database to test competing evolutionary hypotheses. We find that menopause evolved in toothed whales by females extending their lifespan without increasing their reproductive lifespan, as predicted by the 'live-long' hypotheses. We further show 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. Our results provide an informative comparison for the evolution of human life history and demonstrate that the same pathway that led to menopause in humans can also explain the evolution of menopause in toothed whales.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10954554PMC
http://dx.doi.org/10.1038/s41586-024-07159-9DOI Listing

Publication Analysis

Top Keywords

toothed whales
16
menopause evolved
12
evolution menopause
8
menopause toothed
8
menopause
8
menopause humans
8
increasing reproductive
8
toothed
4
whales
4
whales understanding
4

Similar Publications

Odontocetes are globally distributed and are foundational to the structure and function of marine food webs, and hence bycatch impacts from gillnet fishing need to be considered in the context of their conservation and population viability. Currently, global gillnet bycatch numbers are unknown yet are estimated to be the greatest in Asia, East Africa, and the west coasts of North and South America. Here we provide the first global meta-analyses of small- and large-scale gillnet bycatch estimates of odontocetes during 1990-2020, compiling population size, estimated gillnet bycatch, and conservation status in support of geographical and species-specific risk estimates.

View Article and Find Full Text PDF

In tissues of toothed whales from the Adriatic Sea (muscle, liver, kidney, lung, spleen, adipose tissue and skin) the concentrations of cadmium (Cd), lead (Pb) and arsenic (As) were analysed. In total, 186 dolphins were analysed; 155 bottlenose (Tursiops truncatus), 25 striped (Stenella coeruleoalba) and 6 Risso's dolphins (Grampus griseus). Cadmium concentrations in tissue samples ranged from 0.

View Article and Find Full Text PDF

Apex marine predators, such as toothed whales and large petrels and albatrosses, ingest mercury (Hg) primarily in the form of methylmercury (MeHg) via prey consumption, which they detoxify as tiemannite (HgSe). However, it remains unclear how lower trophic level marine predators, termed mesopredators, with elevated Hg concentrations detoxify MeHg and what chemical species are formed. To address this need, we used high energy-resolution X-ray absorption near edge structure spectroscopy paired with nitrogen (N) and Hg stable isotopes to identify the chemical forms of Hg, Hg sources, and species-specific δHg isotopic values in emperor penguin, a mesopredator feeding primarily on Antarctic silverfish.

View Article and Find Full Text PDF

As fully aquatic mammals, hearing is arguably the most important sensory component of cetaceans. Increasingly, researchers have been harnessing computed tomography (CT) to investigate the details of the inner ear as they can provide clues to the hearing abilities of whales. We use microCT scans of a broad sampling of the ear bones (periotics) of primarily toothed whales (Odontoceti) to investigate the inner ear bony labyrinth shape and reconstruct hearing sensitivities among these cetaceans, including several taxa about which little is currently known.

View Article and Find Full Text PDF

Major evolutionary transitions, such as the shift of cetaceans from terrestrial to marine life, can put pressure on sensory systems to adapt to a new set of relevant stimuli. Relatively little is known about the role of smell in the evolution of mysticetes (baleen whales). While their toothed cousins, the odontocetes, lack the anatomical features to smell, it is less clear whether baleen whales have retained this sense, and if so, when the pressure on olfaction diverged in the cetacean evolutionary lineage.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!