Longer rorqual whale mothers produce more female offspring

Proceedings of the Royal Society B
By: , and 

Metrics

1
Crossref references
Web analytics dashboard Metrics definitions

Links

Abstract

Multiple hypotheses have arisen that predict how mammals with the ability to adapt fetal sex ratios should invest in male versus female offspring to maximize inclusive fitness, but large wild-population datasets necessary for testing these hypotheses are challenging to collect. We used whaling data (n = 209 254 sexed fetuses from seven rorqual whale species) to test whether mothers with more resources to invest in offspring produce more male or female offspring. We first modelled fetal sex misidentification in the data and estimated that missexing occurred for fetuses under 30–120 cm across five of seven species. Using Bayesian generalized linear mixed models and a size-restricted dataset to account for misidentification, we estimated a 90% posterior probability that longer mothers have more female offspring overall, ranging from 77% for humpback whales to 99% for sei whales. Our results likely reflect both the difficulty of excluding small males from competition in aquatic environments and the exceptionally high costs of gestation and lactation in baleen whales.


Publication type Article
Publication Subtype Journal Article
Title Longer rorqual whale mothers produce more female offspring
Series title Proceedings of the Royal Society B
DOI 10.1098/rspb.2025.1437
Volume 292
Issue 2055
Publication Date September 24, 2025
Year Published 2025
Language English
Publisher The Royal Society Publishing
Contributing office(s) Coop Res Unit Atlanta
Description 20251437
Additional publication details