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.
- Northern elephant seals are sexually dimorphic meaning that the female exhibits different characteristics than the male.
- 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.
- 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. https://doi.org/10.1098/rsos.210522