Alpha (ethology)

Male "silverback" gorillas are usually the alpha animal and may receive preferential treatment such as being groomed by other group members

In studies of social animals, the highest ranking individual is sometimes designated as the alpha. Males, females, or both, can be alphas, depending on the species. Where one male and one female fulfill this role together, they are sometimes referred to as the alpha pair. Other animals in the same social group may exhibit deference or other species-specific subordinate behaviours towards the alpha or alphas.

Alpha animals usually gain preferential access to food and other desirable items or activities, though the extent of this varies widely between species. Male or female alphas may gain preferential access to sex or mates; in some species, only alphas or an alpha pair reproduce.

Alphas may achieve their status by superior physical strength and aggression, or through social efforts and building alliances within the group.[1]

The individual with alpha status sometimes changes, often through a fight between the dominant and a subordinate animal. Such fights may or may not be to the death.

Beta and omega

Social animals in a hierarchic community are sometimes assigned ranks in ethology studies.

Beta animals often act as second-in-command to the reigning alpha or alphas and will act as new alpha animals if an alpha dies or is otherwise no longer considered an alpha. In some species of birds, males pair up in twos when courting, the beta male aiding the alpha male. It has been found that the social context of the animals has a significant impact on courtship behavior and the overall reproductive success of that animal.[2]

Omega (usually rendered ω) is an antonym used to refer to the lowest caste of the hierarchical society. Omega animals are subordinate to all others in the community, and are expected by others in the group to remain submissive to everyone. Omega animals may also be used as communal scapegoats or outlets for frustration, or given the lowest priority when distributing food.[3]

Examples

Primates

Common chimpanzees show deference to the alpha of the community by ritualized gestures such as bowing, allowing the alpha to walk first in a procession, or standing aside when the alpha challenges.

Gorillas use intimidation to establish and maintain alpha position. A study conducted regarding the reproductive behavior of male mountain gorillas (Gorilla beringei beringei) found further evidence that dominant males are favored to bear offspring, even when there is a greater number of males in a notably enlarged group size. The study also concluded that mating access dropped off less steeply with status; alpha, beta, and gamma showing more similar mating success, compared to what had been previously thought.[4]

A study on the association of alpha male and female during the non-breeding season in wild Capuchin monkeys (Cebus apella nigritus) examined whether alpha males are the preferred mate for females and, secondly, whether female-alpha status and relationship to the alpha-male can be explained through the individual characteristics and or social network of the female.[5] The results indicated that alpha male Capuchin are the preferred mate for adult females. However, only the alpha females had strong interactions with the alpha males by virtue of a dominance hierarchy among the females in which only the most dominant and strong females were able to interact with the alpha male.[5]

Canines

In the past, the prevailing view on gray wolf packs was that they consisted of individuals vying with each other for dominance, with dominant gray wolves being referred to as the "alpha" male and female, and the subordinates as "beta" and "omega" wolves. This terminology was first used in 1947 by Rudolf Schenkel of the University of Basel, who based his findings on researching the behavior of captive gray wolves.[6] This view on gray wolf pack dynamics was later popularized by L. David Mech in his 1970 book The Wolf. He formally disavowed this terminology in 1999, explaining that it was heavily based on the behavior of captive packs consisting of unrelated individuals, an error reflecting the once prevailing view that wild pack formation occurred in winter among independent gray wolves. Later research on wild gray wolves revealed that the pack is usually a family consisting of a breeding pair and its offspring of the previous 1–3 years. [7]

In some other wild canids, the alpha male may not have exclusive access to the alpha female;[8] moreover, other pack members as in the African wild dog (Lycaon pictus) may guard the maternity den used by the alpha female.[9]

See also

References

  1. ↑ de Waal, Frans (2007) [1982]. Chimpanzee Politics: Power and Sex Among Apes (25th Anniversary ed.). Baltimore, MD: JHU Press. ISBN 978-0-8018-8656-0. Retrieved 13 July 2011.
  2. ↑ Wilson and colleagues (6 October 2009). "Seizing the Opportunity: Subordinate Male Fowl Respond Rapidly to Variation in Social Context. Ethology". Retrieved 4 August 2012.
  3. ↑ Jim Dutcher, Jamie Dutcher, James Manfull Wolves at our door: the extraordinary story of the couple who lived with wolves pp.89, 145
  4. ↑ Stoinski, T.S.; Rosenbaum, T.; Ngaboyamahina, T.; Vecellio, V.; Ndagijimana, F.; Fawcett, K. (2009). "Patterns of male reproductive behaviour in multi-male groups of mountain gorillas: examining theories of reproductive skew". Behaviour 146 (9): 1193–1215. doi:10.1163/156853909x419992. Retrieved 1 April 2012.
  5. 1 2 Tiddi, Barbara. "Social relationships between adult females and the alpha male in wild tufted Capuchin monkeys". American Journal of Primatology. Retrieved 7 April 2012.
  6. ↑ Schenkel's paper available at http://www.davemech.org/schenkel/
  7. ↑ Mech, L. David. (1999). "Alpha status, dominance, and division of labor in wolf packs". Canadian Journal of Zoology 77 (8): 1196–1203. doi:10.1139/z99-099. Archived from the original on 2005-12-14.
  8. ↑ Gary Greenberg and Maury M. Haraway. 1998. Comparative Psychology: A Handbook, Published by Taylor & Francis ISBN 0-8153-1281-4
  9. ↑ C. Michael Hogan. 2009. Painted Hunting Dog: Lycaon pictus, GlobalTwitcher.com, ed. N. Stromberg

Further reading

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