Intense sociability in a “non-social” snake (Python regius)

Abstract

It has been suggested that social behavior in squamates evolved partly due to increased interaction opportunities at communal dens and/or due to vivipary. Ball pythons are not viviparous, are not known to communally den, and are often assumed to be non-social. However, as ball pythons are highly cryptic, little is actually known about their social behavior. Here, we examine social interactions and their relationship to personality in juvenile ball pythons (Python regius; n = 30) and find evidence, contrary to expectations, that they are highly gregarious. We tested snakes in both an aggregation assay and in individual personality tests. For the aggregation assay, 5 separate mixed-sex groups of 6 snakes were tracked in a large arena for 10 days. For the personality tests, we tested snakes alone for boldness and sociability. We assessed the snakes’ social interaction patterns within and between the group and individual assays. We found that ball pythons spent much of their time in one large aggregate and used a home base to facilitate social interaction. The snakes were less consistent in their behavior during individual testing, resulting in flexible, rather than consistent, behavior across contexts. Social complexity is thought to determine the number and nature of social interactions between conspecifics, which often results in only testing species that exhibit highly visible social behaviors. Our findings demonstrate that such biased sampling, which often ignores cryptic behavior, provides an incomplete picture of the biological and ecological factors that influence social behavior.

Significance statement

Juvenile ball pythons are surprisingly social. Animal social behavior is usually assessed in species with easily detectable social interactions, which risks missing social behaviors in less visible species. The ecologies of these social species are often then used to inform theories about the origins of social behaviors. For example, in snakes, social behavior is most commonly tested in species that are known to aggregate in dens. We tested social interaction in ball pythons, who have very different ecologies than the denning snakes typically tested for social behavior. We found that ball pythons had large, stable social groups which were facilitated by the use of a home base. These results challenge many assumptions about the causes of sociability in reptiles.