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Joeys Neglected When Mums Mingle

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Having a social life comes at a cost for grey kangaroos, with research published in Behavioral Ecology and Sociobiology finding that joey survival is lower among mingling mothers.

Lead author Dr Wendy King of The University of Queensland’s School of Biological Sciences said young kangaroos that spent more time with their mothers grew faster and gained more weight than other joeys of the same age, and were more likely to survive to adulthood.

“For kangaroo sons, spending time with their mother correlates closely with receiving milk, and so sons are likely to benefit nutritionally from this extra maternal care,” King said. “Some daughters, however, associate closely with their mothers even if the mother no longer provides milk, and must benefit in other ways.”

King said that grey kangaroo mothers did not defend their young from aggressive adult females, but mothers could reduce harassment of their offspring just through their presence. “Juveniles feeding alone with their mothers do not need to compete with others for food, and have more time to feed and grow more rapidly,” King said. “However, mother kangaroos rarely interact with their young through activities such as playing and grooming, so it is unlikely juveniles benefit from behavioural development or parasite removal.”

Co-author A/Prof Anne Goldizen said the findings suggest there is a cost...

The full text of this article can be purchased from Informit.