Search tips
Search criteria 


Logo of biolettershomepageaboutsubmitalertseditorial board
Biol Lett. Oct 23, 2010; 6(5): 630–632.
Published online Mar 17, 2010. doi:  10.1098/rsbl.2010.0159
PMCID: PMC2936150
Higher reproductive skew among birds than mammals in cooperatively breeding species
Nichola J. Raihani1,2* and Tim H. Clutton-Brock2
1Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK
2LARG, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
*Author for correspondence (nichola.raihani/at/
Received February 17, 2010; Accepted February 25, 2010.
While competition for limited breeding positions is a common feature of group life, species vary widely in the extent to which reproduction is shared among females (‘reproductive skew’). In recent years, there has been considerable debate over the mechanisms that generate variation in reproductive skew, with most evidence suggesting that subordinates breed when dominants are unable to prevent them from doing so. Here, we suggest that viviparity reduces the ability of dominant females to control subordinate reproduction and that, as a result, dominant female birds are more able than their mammal counterparts to prevent subordinates from breeding. Empirical data support this assertion. This perspective may increase our understanding of how cooperative groups form and are stabilized in nature.
Keywords: reproductive skew, cooperative breeding, dominance, subordinate, animal societies, sociality
Articles from Biology Letters are provided here courtesy of
The Royal Society