Cowan, D. 1. 1987. Group living in the European rabbit (Oryctolagus cuniculus): Mutual benefit or resource localization. Journal of Animal Ecology 56, 779-795.

The social structure and demography of a free-living rabbit population,living on a 10-ha bowl of chalk downland in Oxfordshire, England, were studied for 6 years. The population was divided into eleven and fourteen breeding groups, each containing between one and eight males and one and twelve females. Eighty-nine per cent of males and 96% of females lived in groups containing at least one other rabbit of the same sex. Nest sites were both localized and limited in their availability, which imposed a group-living habit on many females. These female groups attracted males up to an average group sex ratio of 1:5 females per male. Females living in groups containining more than one female had lower 'lifetime reproductive success' (Clutton-Brock, Guinness & Albon 1982) than those that lived with males only. Hence, the costs of group living apparently outweighed the potential benefits. In addition, male survivorship did not increase with group size.