Northern Elephant Seal
Northern elephant seals were hunted to near-extinction in the 1890s, leaving perhaps 10-20 individuals surviving.
Northern elephant seals were hunted to near-extinction in the 1890s, leaving perhaps 10-20 individuals surviving. The population has since recovered to over 200,000, but genetic diversity remains extremely low - lower than expected even from a bottleneck to 20 individuals.
The reason: elephant seal social structure involves intense male-male competition where a single dominant male fathers most offspring in a breeding colony. The number of breeding males determined the effective population size during recovery, which was far smaller than the census size. This demonstrates how unequal reproductive success reduces effective population size.
Notable Traits of Northern Elephant Seal
- Extreme historical bottleneck to ~20 individuals
- Polygynous mating system reduces effective population size
- Only 2 mitochondrial DNA haplotypes despite 200,000+ population
- Body mass = 90% combat outcome determinant
- Inflatable proboscis as status display
- Visual + auditory signal 92% accurate predictor
- Subordinates concede based on display alone
- Males fight directly for harem access
- Winner-take-all mating dynamics
- Extreme size dimorphism
Northern Elephant Seal Appears in 3 Chapters
Elephant seals represent extreme physical currency dominance where body mass determines 90% of combat outcomes, illustrating the unsustainability of pure physical dominance - enormous energy investment for short tenure.
Learn about physical dominance limits →Elephant seals use inflatable nasal proboscis as status display. The combined visual and auditory signal predicts combat outcomes with 92% accuracy, allowing subordinates to concede without fighting.
Explore honest signaling in hierarchies →Elephant seals exemplify intrasexual competition where males fight directly for harems rather than attracting females. Winners control 50+ females while losers get zero - creating winner-take-all dynamics.
Discover intrasexual competition dynamics →