Analyze Diet
PloS one2009; 4(3); e4888; doi: 10.1371/journal.pone.0004888

Adult-young ratio, a major factor regulating social behaviour of young: a horse study.

Abstract: Adults play an important role in regulating the social behaviour of young individuals. However, a few pioneer studies suggest that, more than the mere presence of adults, their proportions in social groups affect the social development of young. Here, we hypothesized that aggression rates and social cohesion were correlated to adult-young ratios. Our biological model was naturally-formed groups of Przewalski horses, Equus f. przewalskii, varying in composition. Results: We investigated the social interactions and spatial relationships of 12 one- and two-year-old Przewalski horses belonging to five families with adult-young ratios (AYR) ranging from 0.67 to 1.33. We found striking variations of aggression rates and spatial relationships related to the adult-young ratio: the lower this ratio, the more the young were aggressive, the more young and adults segregated and the tighter the young bonded to other young. Conclusions: This is the first study demonstrating a correlation between adult-young ratios and aggression rates and social cohesion of young individuals in a naturalistic setting. The increase of aggression and the emergence of social segregation in groups with lower proportions of adults could reflect a related decrease of the influence of adults as regulators of the behaviour of young. This social regulation has both theoretical and practical implications for understanding the modalities of the influence of adults during ontogeny and for recommending optimal settings, as for instance, for schooling or animal group management.
Publication Date: 2009-03-18 PubMed ID: 19293930PubMed Central: PMC2654111DOI: 10.1371/journal.pone.0004888Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research study focuses on how the ratio of adults to young members in a group can influence social behaviour, specifically within groups of Przewalski horses. It was found that lower ratios of adults led to increased aggression and social segregation among the younger members.

Research Objectives and Hypothesis

  • The research primarily aimed to establish if there was a correlation between the adult-to-young ratio in horse groups and the rate of aggression and social cohesion among the young horses.
  • The hypothesis proposed was that higher aggression rates and less social cohesion were related to lower adult-young ratios.

Methodology

  • To test the hypothesis, the researchers studied the social interactions and spatial relationships of 12 one- and two-year-old Przewalski horses.
  • These horses belonged to five families with varying adult-young ratios ranging between 0.67 to 1.33.

Results

  • The results showed significant variations in aggression rates and spatial relationships, connected to the adult-young ratio.
  • It was noted that a lower ratio resulted in the young becoming more aggressive. Additionally, there was more segregation between young and adult horses, and the young formed stronger bonds with their own age group.

Conclusions and Implications

  • This is the first known study showing a correlation between adult-young ratios and aggression rates and social cohesion among young horses in a naturalistic setting.
  • The study concluded that the increase in aggression and social segregation in groups with fewer adults could be due to a decreased influence of adults in managing the behavior of the young.
  • The findings of this study bear significance for both theoretical understanding of adult influence during ontogeny and practical applications in settings like schooling or animal group management where the adult-young ratio is a factor.

Cite This Article

APA
Bourjade M, de Boyer des Roches A, Hausberger M. (2009). Adult-young ratio, a major factor regulating social behaviour of young: a horse study. PLoS One, 4(3), e4888. https://doi.org/10.1371/journal.pone.0004888

Publication

ISSN: 1932-6203
NlmUniqueID: 101285081
Country: United States
Language: English
Volume: 4
Issue: 3
Pages: e4888
PII: e4888

Researcher Affiliations

Bourjade, Marie
  • Université de Rennes 1, Laboratoire d'Ethologie Animale et Humaine, Centre National de la Recherche Scientifique, Rennes, France. marie.bourjade@gmail.com
de Boyer des Roches, Alice
    Hausberger, Martine

      MeSH Terms

      • Age Factors
      • Animals
      • Behavior, Animal
      • Horses / physiology
      • Social Behavior

      Conflict of Interest Statement

      The authors have declared that no competing interests exist.

      References

      This article includes 36 references
      1. West MJ, King AP, White DJ. The case for developmental ecology.. Anim Behav 2003;66:617–622.
      2. Bradshaw GA, Schore AN, Brown JL, Poole JH, Moss CJ. Elephant breakdown.. Nature 2005 Feb 24;433(7028):807.
        pubmed: 15729320doi: 10.1038/433807agoogle scholar: lookup
      3. Thorallsdottir AG, Provenza FD, Balph DF. Ability of lambs to learn novel food while observing or participating with social models.. Appl Anim Behav Sci 1990;25:25–33.
      4. Voelkl B, Schrauf C, Huber L. Social contact influences the response of infant marmosets towards novel food.. Anim Behav 2006;72:365–372.
      5. Seyfarth RM, Cheney DL. Vocal development in vervet monkeys.. Anim Behav 1986;34:1640–1658.
      6. McComb K, Moss C, Durant SM, Baker L, Sayialel S. Matriarchs as repositories of social knowledge in African elephants.. Science 2001 Apr 20;292(5516):491-4.
        pubmed: 11313492doi: 10.1126/science.1057895google scholar: lookup
      7. West MJ, King AP, Freeberg TM. Building a social agenda for the study of bird song.. In: Snowdon CT, Hausberger M, editors. Social influences on vocal development. Cambridge: Cambridge University Press; 1997. pp. 157–177.
      8. White DJ, King AP, West MJ. Facultative development of courtship and communication in juvenile male cowbirds (Molothrus ater).. Behav Ecol 2002;13:487–496.
      9. Kuhl PK. Human speech and birdsong: communication and the social brain.. Proc Natl Acad Sci U S A 2003 Aug 19;100(17):9645-6.
        pmc: PMC187796pubmed: 12913121doi: 10.1073/pnas.1733998100google scholar: lookup
      10. Pettit GS, Bates JE, Dodge KA, Meece DW. The impact of after-school peer contact on early adolescent externalizing problems is moderated by parental monitoring, perceived neighborhood safety, and prior adjustment.. Child Dev 1999 May-Jun;70(3):768-78.
        pmc: PMC2761644pubmed: 10368921doi: 10.1111/1467-8624.00055google scholar: lookup
      11. White DJ, King AP, Cole A, West MJ. Opening the social gateway: early vocal and social sensitivities in brown-headed cowbirds (Molothrus ater).. Ethology 2002;108:23–37.
      12. Hausberger M, Henry L, Cousillas H, Mathelier M, Bourjade M. Social experience, vocal learning and social cognition in the European starling, Sturnus vulgaris.. Acta Zool Sin 2006;52(supplement):618–621.
      13. Slotow R, van Dyk G, Poole J, Page B, Klocke A. Older bull elephants control young males.. Nature 2000 Nov 23;408(6811):425-6.
        pubmed: 11100713doi: 10.1038/35044191google scholar: lookup
      14. Bourjade M, Moulinot M, Henry S, Richard-Yris MA, Hausberger M. Could adults be used to improve social skills of young horses, Equus caballus?. Dev Psychobiol 2008 May;50(4):408-17.
        pubmed: 18393282doi: 10.1002/dev.20301google scholar: lookup
      15. Bertin A, Hausberger M, Henry L, Richard-Yris MA. Adult and peer influences on starling song development.. Dev Psychobiol 2007 May;49(4):362-74.
        pubmed: 17455227doi: 10.1002/dev.20223google scholar: lookup
      16. Bertin A, Hausberger M, Henry L, Richard-Yris MA. Adult: young ratio influences song acquisition in female European starlings (Sturnus vulgaris).. J Comp Psychol 2009 May;123(2):195-203.
        pubmed: 19450026doi: 10.1037/a0014050google scholar: lookup
      17. Burchinal MR, Roberts JE, Riggin R Jr, Zeisel SA, Neebe E, Bryant D. Relating quality of center-based child care to early cognitive and language development longitudinally.. Child Dev 2000 Mar-Apr;71(2):339-57.
        pubmed: 10834469doi: 10.1111/1467-8624.00149google scholar: lookup
      18. NICHD Early Child Care Research Network. Characteristics of Infant Child Care: Factors Contributing to Positive Caregiving.. Early Childhood Research Quarterly 1996;11:269–306.
      19. Howes C, Rubenstein J. Determinants of toddlers' experiences in care: Age of entry and quality of setting.. Child Care Quarterly 1985;14:140–151.
      20. Burchinal MR, Campbell FA, Brayant DM, Wasik BH, Ramey CT. Early Intervention and Mediating Processes in Cognitive Performance of Children of Low-Income African American Families.. Child Dev 1997 Oct;68(5):935-954.
      21. Lemasson A, Gautier JP, Hausberger M. A brief note on the effects of the removal of individuals on social behaviour in a captive group of campbell's monkeys (Cercopithecus campbelli campbelli): a case study.. Appl Anim Behav Sci 2005;91:289–296.
      22. Boyd L, Keiper R. Behavioural ecology of feral horses.. In: Mills D, McDonnell S, editors. The domestic horse. The evolution, development and management of its behaviour. Cambridge: Cambridge University Press; 2005. pp. 55–82.
      23. Henry S, Hemery D, Richard M-A, Hausberger M. Human-mare relationships and behaviour of foals toward humans.. Appl Anim Behav Sci 2005;93:341–362.
      24. Henry S, Briefer S, Richard-Yris MA, Hausberger M. Are 6-month-old foals sensitive to dam's influence?. Dev Psychobiol 2007 Jul;49(5):514-21.
        pubmed: 17577237doi: 10.1002/dev.20225google scholar: lookup
      25. Feh C. Relationships and communication in socially natural horse herds.. In: Mills D, McDonnell S, editors. The domestic horse. The evolution, development and management of its behaviour. Cambridge: Cambridge University Press; 2005. pp. 83–93.
      26. Feist JD. Behavior of feral horses in the Pryor Mountain wild horse range.. 1971. p. 130. PhD Thesis, University of Michigan.
      27. Coussi-Korbel S, Fragaszy DM. On the relation between social dynamics and social learning.. Anim Behav 1995;50:1441–1453.
      28. Hausberger M, Richard MA, Henry L, Lepage L, Schmidt I. Song sharing reflects the social organisation in a captive group of European starlings (Sturnus vulgaris).. J Comp Psychol 1995;109:222–241.
      29. Poirier C, Henry L, Mathelier M, Lumineau S, Cousillas H, Hausberger M. Direct social contacts override auditory information in the song-learning process in starlings (Sturnus vulgaris).. J Comp Psychol 2004 Jun;118(2):179-93.
        pubmed: 15250805doi: 10.1037/0735-7036.118.2.179google scholar: lookup
      30. Cousillas H, George I, Henry L, Richard JP, Hausberger M. Linking social and vocal brains: could social segregation prevent a proper development of a central auditory area in a female songbird?. PLoS One 2008 May 21;3(5):e2194.
      31. Rubenstein J, Howes C. The effects of peers on toddler interaction with mother and Toys.. Child Dev 1976;47:597–605.
      32. Mc Cartney C. Effect of quality of day care environment on children's language development.. Dev Psychobiol 1984;20:244–260.
      33. Monfort SL, Arthur NP, Wildt DE. Reproduction in the Przewalski's horse.. In: Boyd L, Houpt KA, editors. Przewalski's horse, the history and biology of an endangered species. New York: State University of New York Press; 1994. pp. 173–193.
      34. Altmann J. Observational study of behavior: sampling methods.. Behaviour 1974;49(3):227-67.
        pubmed: 4597405doi: 10.1163/156853974x00534google scholar: lookup
      35. Cohen J. A coefficient of agreement for nominal scales.. Educ Psychol Meas 1960;20:37–46.
      36. Siegel S, Castellan NJ. Nonparametric statistics for the behavioral sciences.. Singapore: McGraw-Hill international; 1988. p. 399.

      Citations

      This article has been cited 8 times.
      1. Siracusa ER, Pereira AS, Brask JB, Negron-Del Valle JE, Phillips D, Platt ML, Higham JP, Snyder-Mackler N, Brent LJN. Ageing in a collective: the impact of ageing individuals on social network structure.. Philos Trans R Soc Lond B Biol Sci 2023 Apr 10;378(1874):20220061.
        doi: 10.1098/rstb.2022.0061pubmed: 36802789google scholar: lookup
      2. Stachurska A, Kędzierski W, Kaczmarek B, Wiśniewska A, Żylińska B, Janczarek I. Variation of Physiological and Behavioural Parameters during the Oestrous Cycle in Mares.. Animals (Basel) 2023 Jan 6;13(2).
        doi: 10.3390/ani13020211pubmed: 36670751google scholar: lookup
      3. Allen CRB, Croft DP, Brent LJN. Reduced older male presence linked to increased rates of aggression to non-conspecific targets in male elephants.. Proc Biol Sci 2021 Dec 22;288(1965):20211374.
        doi: 10.1098/rspb.2021.1374pubmed: 34933598google scholar: lookup
      4. Lesimple C. Indicators of Horse Welfare: State-of-the-Art.. Animals (Basel) 2020 Feb 13;10(2).
        doi: 10.3390/ani10020294pubmed: 32069888google scholar: lookup
      5. Bourjade M, Thierry B, Hausberger M, Petit O. Is leadership a reliable concept in animals? An empirical study in the horse.. PLoS One 2015;10(5):e0126344.
        doi: 10.1371/journal.pone.0126344pubmed: 26010442google scholar: lookup
      6. Briefer Freymond S, Briefer EF, Von Niederhäusern R, Bachmann I. Pattern of social interactions after group integration: a possibility to keep stallions in group.. PLoS One 2013;8(1):e54688.
        doi: 10.1371/journal.pone.0054688pubmed: 23382940google scholar: lookup
      7. George I, Cousillas H, Richard JP, Hausberger M. Experience with adults shapes multisensory representation of social familiarity in the brain of a songbird.. PLoS One 2012;7(6):e38764.
        doi: 10.1371/journal.pone.0038764pubmed: 22723887google scholar: lookup
      8. Lemasson A, Gandon E, Hausberger M. Attention to elders' voice in non-human primates.. Biol Lett 2010 Jun 23;6(3):328.
        doi: 10.1098/rsbl.2009.0875pubmed: 20053662google scholar: lookup