Social structure, vigilance and behaviour of plains zebra (Equus burchellii): a 5-year case study of individuals living on a managed wildlife reserve

Abstract

This is a copy of the authors' accepted version of this manuscript, and the definitive published version in Acta Theriologica may have changed slightly in response to editing. This version is made available on the University of Bristol's repository, complying with Springer's policy on selfarchiving (7th April 2008).The original article is available at springerlink.com. Please see http://dx.doi.org/10.1007/s13364-011-0061-x for the definitive version, and details of how to cite this work ABSTRACT Most studies of plains zebra (Equus burchellii) have focused on population ecology and have not included long-term observations of identified individuals. Over a five year period we studied the crepuscular activities of 13 individual zebras within a focal group held within a managed game reserve. We also examined individual residency within the group by recording births, mortalities and longevity of group membership by adults. Residency of individuals living in other groups on the reserve was similarly monitored to examine variability in social structure within this closed population over an extended period of time. Stable, female groups were the mainstay of group sociality with male mean residency at 31.6 months being variable in length or even absent. Social interactions across all categories of zebra were free from aggression. Despite an absence of nonhuman predators, the proportion of dusk time-budget allocated to vigilance was high, at 41% for males during periods when they accompanied stable female groups and 12% for females during these same periods. Female vigilance increased significantly to 19% when males were not resident. Females spent 70% of the time grazing and males just 36%. Due to its long-term nature, we concluded this study established a base line for plains zebra activity that could assist in understanding the factors that influence the successful management and conservation of healthy populations.

Sex/age differences in foraging, vigilance and alertness in a social herbivore

“…Other studies have reported greater vigilance levels in males than in females (e.g. guanaco Lama guanicoe: Marino and Baldi 2008;vicuña Vicugna vicugna: Vilá and Cassini 1994; impala Aepyceros malampus: Shorrocks and Cokayne 2005; Tibetan gazelle Procapra picticaudata: Li and Jang 2008; Przewalski's gazelle Procapra przewalskii: Shi et al 2011; plains zebra Equus bruchellii: Simpson et al 2012). However, many of these studies have been conducted during the mating season, when territorial males, or males holding a harem, are expected to spend long periods watching the females and looking out for rival males (Shorrocks and Cokayne 2005;Lung and Childress 2007).…”

Plains zebras bring evidence that dilution and detection effects may not always matter behaviorally and demographically

“…Contrary to our prediction, we found no apparent costs related to intra-group interference competition for access to resources in our study population. Agonistic interactions were rare, as found in other plains zebra populations (Fischhoff et al 2009, Simpson et al 2012. Due to this rarity, we could not test our hypothesis that the frequency of agonistic interactions increases as group size increases.…”

Social Organization and Activity Patterns of Common Warthog (<i>Phacochoerus africanus Gmelin, </i>1788) in Dabena Valley Forest, Western Ethiopia

“…This might be due high rate of vigilance in predation risk area. Females need high energy requirements for their offspring and prioritize foraging and they benefit from the presence of vigilant males [31,37].…”