Stallion harassment and the mating system of horses.
Abstract: Feral horse, Equus caballus, breeding groups, called bands, usually include one but sometimes up to five stallions. We found that mares were loyal to single-stallion (SS) or multistallion (MS) bands or were social dispersers (maverick mares, Mv). The spacing and social behaviour of mares and stallions in single- and multistallion bands was measured. Indices of mare well-being were also measured including activity budgets (feeding: MS>SS=Mv; resting: MSSS), maternal effort in maintaining contact with foals (MS=Mv>SS), parasite levels in faeces (MS>Mv>SS), body condition (MS=Mv<SS), fecundity (Mv<MS<SS) and offspring mortality (Mv<MS<SS). We present evidence suggesting that the poorer well-being of maverick mares and multistallion band mares results from greater harassment by stallions. Stallion and mare behaviour and poor reproductive success in multistallion bands were not consistent with explanations for the existence of such bands based on cooperation or alternative mating strategies. We suggest an alternative explanation. Stable relationships between mares and a single stallion may enhance reproductive success by reducing aggression between individuals. Therefore, we propose that there is strong selection pressure for stable, long-term stallion-mare relationships, called consort relationships. We propose the consort hypothesis, that multistallion bands are an artefact of selection for stable relationships that occasionally result in more than one such relationship forming, because mares solicit more than one stallion and stallion dominance changes during band formation. Copyright 1999 The Association for the Study of Animal Behaviour.
Publication Date: 1999-11-30 PubMed ID: 10458881DOI: 10.1006/anbe.1999.1155Google Scholar: Lookup
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- Journal Article
Summary
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The research article studies the mating system of wild horses (Equus caballus), examining how stallion harassment affects this system and the overall well-being of mares, with particular focus on the differences between mares in single-stallion and multi-stallion groups.
Objective of the Study
- The study aims to assess the dynamics of stallion-mare relationships within wild horse groups, known as ‘bands’, specifically focusing on differences between single-stallion (SS) and multi-stallion (MS) bands. The researchers also pay attention to ‘maverick mares’ (Mv), female horses that move between different social groups.
Methodology
- The researchers observed and measured the social behaviour and spacing within different types of horse bands. They also tracked specific indices of mare well-being such as activity budgets (feeding and resting times), travel distance, effort in maintaining contact with foals, parasite levels in faeces, bodily condition, fecundity, and offspring mortality.
Findings
- The results suggest that maverick mares and those within MS bands experience poorer well-being due to higher levels of stallion harassment. This conclusion is drawn from observations such as mares in MS bands and Mv mares generally spending more time feeding, traveling, and maintaining contact with their offspring, having higher parasite levels, worse body condition, lower fecundity, and higher offspring mortality compared to mares in SS bands.
Implications and Hypothesis
- The researchers propose that stable long-term relationships between individual mares and a single stallion (known as ‘consort relationships’) could enhance reproductive success by lowering aggression between horses. Thus, they suggest that there could be a strong evolutionary pressure selecting for such relationships.
- The ‘consort hypothesis’ is then proposed, suggesting that MS bands could be an inadvertent outcome of selection for stable relationships, occurring when more than one consort relationship forms due to mares soliciting more than one stallion and shifts in stallion dominance.
Conclusion
- This study provides critical insights into wild horse social and mating behavior, suggesting that the formation of MS bands and the poorer well-being experienced by mares within such groups and by maverick mares could be attributed to higher stallion harassment. Further research could shed more light on the dynamics of these social structures and their impact on horse well-being and reproductive success.
Cite This Article
APA
Linklater WL, Cameron EZ, Minot EO, Stafford KJ.
(1999).
Stallion harassment and the mating system of horses.
Anim Behav, 58(2), 295-306.
https://doi.org/10.1006/anbe.1999.1155 Publication
Researcher Affiliations
- Ecology Group, Institute of Natural Resources, Massey University
Citations
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