Play is an biologically expensive behaviour: its physically risky and costly in energy and time. Play in immature homeotherm vertebrates (mammals and birds) is common, yet it almost universally stops at somatic maturation. There is an exception to this apparent evolutionary rule: in species with complex sociality and cognition, this behavior seems more prevalent, including in adults.
Why would complex social systems invest in apparently wasteful behaviors?
I pursued this question by studying social lives and play behaviour of bonobos (Pan paniscus), which are together with chimpanzees our living closet relatives. Bonobos are typically known for their highly sexual nature, which is thought to play a role in their tolerant societies. I collected data on bonobo socio- ecology and behavior in a community of 30 wild, habituated bonobos at Wamba, Democratic Republic of Congo, totaling more than 2,000 hours of direct observation and 20,000 scans over the course of 3 years of fieldwork.
I developed and tested the ‘Adaptive Joker’ hypothesis, which understands play as a complexity-generating behavior. I will discuss results in the context of (1) energy and time budgets (adaptive tradeoffs and ecological correlates) (2) connectivity and coordination of individuals (bonding mechanisms), and (3) diversity of components (in interaction type and partners).
Findings contribute towards understanding the role of flexibility in complex systems, as well as definitions and measures of social complexity in animals other than humans.