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Role-Reversed Nepotism Among Cubs and Sires in the Spotted Hyena (Crocuta crocuta)

Authors


Russell C. Van Horn, Department of Zoology, Michigan State University, 203 Natural Science Building, East Lansing, MI 48824-1115, USA. E-mail: vanhorn3@msu.edu

Abstract

Nepotism is widespread among parents and offspring, and is typically associated with fundamental asymmetries; parents can usually do more to help their offspring than vice versa, and the cost of a given nepotistic behavior is usually less for parents than for offspring. This may not be so among spotted hyenas (Crocuta crocuta); sires never achieve social rank equal to that of their cubs, to whom they provide no obvious paternal care. Nepotism by sires towards their cubs is thus socially constrained. However, the higher social status of cubs might offset cubs’ developmental disadvantages and permit nepotistic treatment of sires by offspring. We therefore sought to determine whether the interactions among spotted hyena cubs and adult males were influenced by kinship, using long-term observations from one clan of spotted hyenas. Sires exhibited no overt nepotism towards their cubs in most behaviors, but they did associate more closely with their daughters than with unrelated control females. Sires also associated more closely with their daughters than with their sons, with whom they associated no more closely than they did with unrelated control males. Cubs favored their sires by directing less intense aggression towards them than towards unrelated control males. Cubs of both sexes also associated more closely with their sires than with control males after the cubs were independent of the clan's communal den. Although sires evidently recognize their offspring, paternal nepotism by sires towards their cubs is weaker than filial nepotism by cubs towards their sires. The small size and immaturity of cubs thus appear to be weaker constraints on nepotism than is the low social status of their sires.

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