Investigating the impact of rank and ovarian activity on the social behavior of captive female African elephants.
Over a third of captive female African elephants in North America fail to exhibit normal estrous cycles based on long-term serum progestagen analyses. Why acyclicity occurs is unknown; however, the majority of noncycling females are ranked by keepers as the dominant individual within the group. To investigate the relationship between ovarian cyclicity status and keeper-determined social rank, observations were conducted on 33 female African elephants (18 cycling, 15 noncycling). Based on keeper evaluations, five cycling elephants were ranked dominant, seven in the middle and six as subordinate. In contrast, 10 noncycling elephants were ranked as dominate and five as subordinate with none ranked as middle. When comparing the behavior of the elephants by their keeper-determined rank, the dominant females dominant were significantly more likely to approach, displace and push. Similarly, keeper-determined subordinate females more frequently presented their hind end and held their ears erect. Behaviors initiated by one elephant toward another did not vary between cycling and noncycling females, except when the interaction with social rank was tested. Dominant, noncycling females initiated a higher percentage of "approach" and "displace" behaviors than both cycling and noncycling, subordinate elephants. Subordinate, noncycling elephants displayed the highest percentage of "ears erect." Social rank drives the interactions of ex situ female African elephants more than ovarian cyclicity status. Thus, behavioral interactions cannot be used to predict which cycling elephants are most likely to become acyclic.
Freeman
Elizabeth W
EW
National Zoological Park, Conservation & Research Center, Front Royal, Virginia, USA. efreeman@gmu.edu
Schulte
Bruce A
BA
Brown
Janine L
JL
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D004606:Elephants / Q000502:physiology*; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D008297:Male; D009656:North America; D012930:Social Dominance