Elephant seals no dumbos: study reveals distinct foraging strategies between the sexes

Embargoed until: Publicly released: 2022-01-19 11:01

International

Photo by anchor lee on Unsplash

In northern elephant seals, differences between male and female foraging strategies represent different means of maximising offspring. Researchers attached satellite and radio transmitters to over 200 elephant seals to track their foraging behaviour and mortality rates, collecting tissue samples to analyse their diets and measuring their size and weight when they returned ashore. Male elephant seals hunt shallow waters along continental shelves, and gain up to six times as much body mass as their female counterparts, who prefer to deep sea dive in open waters. Males had a higher mortality rate, suggesting that they engage in riskier behaviour to gain as much weight as possible in order to attract more females in a short space of time. Females, on the other hand, opt for safer foraging strategies so that they can reproduce annually over a longer lifespan.

Media release

From: The Royal Society

Seal for your supper – In situations of life or death, male northern elephant seals choose food. Researchers analysed a decadal dataset on movement patterns, dive behaviour, foraging success and mortality rates, finding male seals adopt a high-risk high reward strategy when foraging, gaining six times more mass, but with a six times higher mortality rate than females. Male seals prioritise gaining a high body mass to attract females, whereas females prioritise survival to reproduce annually over a long lifespan.

Journal/
conference: Royal Society Open Science

Research:Paper

Organisation/s: Baylor University, University of California

Funder: This research was conducted as part of the Tagging of Pacific Predators program and supported in part by the National Ocean Partnership Program (N00014-02-1-1012); the Office of Naval Research (N00014-00-1-0880, N00014-03-1-0651, N00014-08-1-1195), the E&P Sound and Marine Life Joint Industry Project of the International Association of Oil and Gas Producers (JIP2207-23); the University of California Natural Reserve System, the NOAA Dr. Nancy Foster Scholarship Program, and the Moore, Packard and Sloan Foundations.

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