Spatial and temporal heterogeneities in the contact behaviour of rabbits

It is becoming increasingly evident that the social behaviour of many group-living species is more complex than previously assumed and that free mixing of individuals, even within social groups, is rare. This has important implications for ecological processes, such as disease transmission, which are dependent on interactions between individuals. European wild rabbits (Oryctolagus cuniculus) have been considered traditionally as highly sociable animals that mix freely within groups but interact less frequently between groups. We deployed proximity logging devices to quantify the intra- and inter-group contact behaviour of free-living wild rabbits in two populations in a temperate region of Australia. Altogether, 126 rabbits were fitted with proximity loggers at least once during the study. Radio-tracking was carried out alongside proximity data collection to determine the space use of rabbit social groups within the study sites. On average, a rabbit made only 1.54 ± 0.23 (SE) (median = 0.54) contacts per day with each other rabbit carrying a proximity logger in its social group, and the mean daily contact duration was 202 ± 38 s/day (SE) (median = 29 s). Despite the high degree of home range overlap between the neighbouring social groups, inter-group contacts were highly infrequent and brief. Our results demonstrated considerable spatial and temporal heterogeneities in the contact behaviour between individual rabbits, both between populations and between and within social groups in the same population. Such variations in the social organisation of rabbits are likely to create complex patterns of disease transmission through direct contact and may contribute towards observed heterogeneities in the effects of disease on wild rabbit populations.