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Evolution of weaponry in female bovids
Theodore Stankowich1, Tim Caro
1Organismic and Evolutionary Biology, Department of Biology, University of Massachusetts, Amherst, MA 01003, USA. teds@bio.umass.edu
Proceedings. Biological Sciences
|September 18, 2009
Summary
Female bovids are more likely to have horns if they are large and live in open habitats, suggesting horns primarily evolved for predator defense. Smaller territorial females may use horns for competition.
Area of Science:
- Zoology
- Evolutionary Biology
- Animal Behavior
Background:
- Weaponry is common in male ungulates due to intrasexual selection.
- The sporadic presence and function of horns in female ungulates remain largely unexplained.
- Existing hypotheses for female horns include food competition, male appeasement, and predator defense.
Purpose of the Study:
- To investigate the evolutionary drivers and primary functions of horn development in female bovids.
- To determine the correlation between habitat, body size, and the presence of horns in female bovids.
- To explore the potential role of horns in antipredator defense versus intrasexual competition in females.
Main Methods:
- Comparative phylogenetic analyses were employed to study horn evolution across bovid species.
- Species characteristics such as body size, habitat (open vs. closed), and horn presence in females were analyzed.
- Phylogenetic reconstructions were used to infer the evolutionary history and functional shifts of female horns.
Main Results:
- Female bovids in conspicuous species (large body size, open habitats) are significantly more likely to possess horns than those in inconspicuous species (small body size, closed habitats).
- The evolution of horns in female bovids appears strongly linked to the need for antipredator defense, especially in species unable to rely on camouflage or dense vegetation for cover.
- In some smaller, territorial species, female horns are utilized in intrasexual contests, representing an exception to the primary antipredator function.
Conclusions:
- The primary function of horns in female bovids is antipredator defense, particularly in species with high conspicuousness.
- Habitat and body size are key factors influencing the evolution of female horns, favoring their development in open-habitat, large-bodied species.
- While antipredator defense is the predominant function, intrasexual competition can also drive horn evolution in specific ecological contexts, such as territoriality in smaller species.
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