Adult males are less social than juveniles and adult females in a wild agamid species

Abstract

Across their lifetime, individuals experience differing social environments and may adjust their social behaviour accordingly, leading to age-dependent social behaviour. Studying the ontogeny of social behaviour is of great importance, as it can provide valuable insights into the development and maintenance of sociality. So far, most studies investigating age-dependent social behaviour have focused on animal species exhibiting parental care (e.g. primates, cetaceans). However, in species lacking parental care, juveniles' behaviour likely has a greater impact on their survival than in species with parental care, owing to the lack of parental feeding and protection. Here, we explored whether affiliative behaviour differed between juvenile and adult eastern water dragons, Intellagama lesueurii, a species with no parental care. Specifically, we investigated the effect of age on individuals’ social associations and social environment (i.e. number of available social partners). We found that adult males were less gregarious, found in smaller groups and had fewer associates than both juveniles and adult females. Additionally, adult males fostered weaker associations than juveniles. Most importantly, this phenomenon was observed despite adult males experiencing similar opportunities to socialize as adult females and juveniles on the observation scale, while having more opportunities than juveniles on the yearly scale. Our findings may be driven by an adaptive avoidance of adult males by juveniles and adult females.