Research Highlights: Male northern elephant seals prefer to be fat hoping to mate with the females


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By Frank Schulenburg – Own work, CC BY-SA 3.0,

Male northern elephant seals prefer to be fat hoping to mate with the females

  • Differences in sex-related characteristics are common among animals.
  • Reproductive advantages given by trait differences have downside.
  • Researchers discovered that sex-specific food hunting strategies are linked to trade-offs between food hunting reward and mortality risk in northern elephant seals.
  • Elephant seals are large earless seals which belongs to the genus Mirounga.[1]
  • Northern elephant seals are sexually dimorphic meaning that the female exhibits different characteristics than the male.[2]
  • Researchers analyzed a dataset on movement pattern, diving behavior, food hunting success, and mortality rate.
  • The dataset was produced from monitoring the elephant seals over a period of almost 10 years.
  • Females dive deep to hunt for food in open ocean habitat; however, males dive shallow to hunt food near the shores.
  • Researchers observed that males gain six times more mass than females.
  • They also found that males obtain energy about 4 times faster than females.
  • These food hunting strategies and trade-offs are associated to various energy demands and life-history strategies.
  • Life-history is the pattern of survival and reproduction, along with the traits that directly affect survival rate and reproductive success.[3]
  • Males utilize food hunting strategies with a high mortality risk to achieve larger body size to compete for females.
  • There is a small percentage of the largest males that successfully mate.
  • Females utilize food hunting strategies with a low mortality risk to maximize reproductive success.
  • The results suggest that mortality rates can be affected by sex-specific traits.
  • Additionally, trade-offs between food hunting rewards and mortality risk can affect each sex’s ability to maximize fitness.
  • In summary, males are willing to risk death to consume more food hoping they can successfully mate with the females.


Kienle, S. S., Friedlaender, A. S., Crocker, D. E., Mehta, R. S., & Costa, D. P. (2022). Trade-offs between foraging reward and mortality risk drive sex-specific foraging strategies in sexually dimorphic northern elephant seals. Royal Society open science, 9 (1), 210522.





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