Induced abortion and social factors in wild horses.
Abstract: Much evidence now suggests that the postnatal killing of young in primates and carnivores, and induced abortions in some rodents, are evolved traits exerting strong selective pressures on adult male and female behaviour. Among ungulates it is perplexing that either no species have developed convergent tactics or that these behaviours are not reported, especially as ungulates have social systems similar to those of members of the above groups. Only in captive horses (Equus caballus) has infant killing been reported. It has been estimated that 40,000 wild horses live in remote areas of the Great Basin Desert of North America (US Department of Interior (Bureau of Land Management), unpublished report), where they occur in harems (females and young) defended by males. Here I present evidence that, rather than killing infants directly, invading males induce abortions in females unprotected by their resident stallions and these females are then inseminated by the new males.
Publication Date: 1983-05-05 PubMed ID: 6682487DOI: 10.1038/303059a0Google Scholar: Lookup
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- Journal Article
Summary
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This research explores the phenomenon of induced abortions in wild horses, suggesting that invading male horses cause unprotected female horses to abort their offspring and then impregnate them.
Background
- The study is based on earlier research findings which suggest that the killing of infants after birth in primates and carnivores, and induced abortions in some rodents, are evolved traits that significantly influence adult male and female behavior.
- Among ungulates (hoofed mammals), these behaviors are either not observed or not reported despite their social systems being similar to those in carnivores and primates.
- Prior to this study, the only observed case of infanticide among ungulates was in captive horses.
Aim of the Study and Research Methodology
- The researchers set out to study about 40,000 wild horses that live in the remote areas of the Great Basin Desert of North America. The social organization of these horses is similar to that of primates and carnivores, with males defending harems that consist of females and their young.
- The aim of the study was to understand whether similar patterns of induced abortions and infanticide are present in the behavior of these wild horses.
Findings
- The study discloses that invading male horses, rather than killing infants directly after their birth, could induce abortions in the females that were previously unprotected by their resident stallions.
- The study posits that these invading males then impregnate the females affected in this way.
The research builds on earlier findings regarding infant mortality and induced abortions in mammals and extends these behavioral patterns to wild horses. It shows how such brutal survival tactics have evolved and how they might play a critical role in shaping the behavior of male and female horses.
Cite This Article
APA
Berger J.
(1983).
Induced abortion and social factors in wild horses.
Nature, 303(5912), 59-61.
https://doi.org/10.1038/303059a0 Publication
Researcher Affiliations
MeSH Terms
- Abortion, Induced / veterinary
- Abortion, Veterinary / etiology
- Aggression / physiology
- Animals
- Biological Evolution
- Female
- Horses / physiology
- Humans
- Pregnancy
- Sexual Behavior, Animal / physiology
Citations
This article has been cited 15 times.- Saltz D, Rowen M, Rubenstein DI. The Effect of Space-Use Patterns of Reintroduced Asiatic Wild Ass on Effective Population Size.. Conserv Biol 2000 Dec 18;14(6):1852-1861.
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