Date of Award
Master of Science
Michael R. Pelton
Gordon Burghardt, John Gittleman
Patterns of behavioral development in closely related North American Canis have been studied extensively. Developmental trends have been used to assess species-typical social organization and taxonomic relationships i wolves (C. lupus), coyotes (C. latrans) and domestic dogs (C. familiaris). Despite its species designation, the taxonomic status of the closely related red wolf (C. rufus) is fiercely debated and a hybrid origin (C. lupus x C. latrans) has been proposed. The objective of the current study therefore was to analyze growth and behavioral development patterns in the red wolf and perform general comparisons to trends previously documented in wolves and coyotes.
Two captive born red wolf (Canis rufus) litters (litter 1: n=5 pups, 2 adults; litter 2: n=4 pups, 2 adults) were observed from 28-50 days of age. Data were collected on the form, frequency and duration of select pup-pup and pup-adult social interactions as well as pup-object play. Growth patterns and trends of physical development were also examined in litter 1.
Growth patterns were consistent with that reported for other closely related canid species: age at eyeopening, age of independent urinary and defecation control, and the consumption of solid food were similar to that documented for wolves and coyotes. Red wolf pup weights were intermediate to that described for wolves and coyotes. Teeth erupted on average later and in a different order than that previously described in coyotes.
Observed behavioral trends were intermediate to that of coyotes and wolves and shared characteristics of each. The form of pup behavior patterns did not differ qualitatively from that previously documented for either gray wolves or coyotes. However, pups simultaneously exhibited "species-specific" behavior patterns previously attributed to both wolves (leap leap, prolonged jaw wrestling) and coyotes (inguinal response, defensive gape). Early red wolf social interactions were predominantly agonistic and primarily in the form of threats rather than overt aggression. There was no evidence of a dominance hierarchy in either litter. In both litters, the frequency of play increased concurrently with a decrease in frequency of agonistic interactions. Individual differences were not noted in the frequency of play or aggression in either litter; however, the two litters differed significantly in the frequency of play and aggression.
Object play followed the differential development of play and aggression. Early object play was non-social (pup-object) and peaked during the transitional period during which the frequency of aggression was decreasing and social play increasing. Social object play (pup-pup-object) was observed later in development as reciprocal social play also increased.
Adult-pup interactions varied by litter. In general, pups spent more time in proximity to the female than the male throughout the study period in both litters; however proximity to each adult changed over time. Initially, pups spent more time in proximity to the female. As pups aged, the amount of time spent in proximity to the female decreased while proximity to the male and both the male and female increased. In litter 1, adult-pup agonistic interactions were observed almost to the exclusion of other interactions. Conversely, investigative and afflliative interactions predominated in litter 2. In both litters, male-pup interactions were frequent.
In sum, the patterns of physical and behavioral development in the red wolves observed in this study share similarities with both gray wolves and coyotes. Therefore, the data presented do not exclude a hybrid origin hypothesis. Suggestions for further research include the development of play and agonistic action patterns from days 21-28 as well as post 50 days of age, further investigation of subtle indicators of dominance and increased numbers of subjects.
Wagener, Tarren Kay, "The Ontogeny of Red Wolf (Canis rufus) Social Behavior: Implications for Sociality and Taxonomic Status. " Master's Thesis, University of Tennessee, 1998.