Few sex effects in the ontogeny of mother-offspring relationships in eastern grey kangaroos
Publication Type: |
Journal Article |
Year of Publication: |
2016 |
Authors: |
Wendy J. King, Anne W. Goldizen |
Publication/Journal: |
Animal Behaviour |
Keywords: |
associative behaviour, distress call, kin cluster, macropus-giganteus, mother-offspring relationship, spatial proximity, weaning |
ISBN: |
0003-3472 |
Abstract:
Social relationships established early in life can have effects on social structure and influence individual fitness. Eastern grey kangaroos, Macropus giganteus, nurse their young for at least 18 months, allowing for a strong bond to develop between mothers and young. Because most female kangaroos are philopatric, the mother-offspring relationship established during lactation could persist into adulthood, resulting in clusters of female kin. Strong social bonds, however, are based on affiliative behaviours and frequent interactions. In particular, one might not expect strong bonds among related individuals unless there are advantages to interacting with relatives compared to associating with unrelated conspecifics. We examined development of the mother-offspring relationship in eastern grey kangaroos from permanent emergence from the pouch to the time of weaning. We studied a high-density population at Wilsons Promontory National Park, Victoria, Australia. There were few differences in the behaviour of sons and daughters towards mothers. However, daughters foraged slightly closer than sons to their mothers and daughters were weaned approximately 2 months later than sons if the mother did not have a surviving large pouch young. Mothers associated more closely with their daughters than their sons when offspring were aged 10–29 months but neither sex associated closely with their mothers beyond 33 months of age. Mothers never intervened to defend their young from aggressive individuals and it was the offspring that maintained spatial proximity to their mothers. Kangaroo mothers had few interactions with their juvenile offspring other than nursing. Females may be philopatric and settle near close kin as adults but kangaroos appear to have few of those early affiliative interactions necessary for social bonds to develop.