Social interactions in striped hyena inferred from camera trap data: is it more social than previously thought?

Understanding the drivers promoting sociality over solitariness in animal species is imperative for predicting future population trends and informing conservation and management. In this study we investigate the social structure of a desert dwelling population of striped hyena Hyaena hyaena. This species is historically regarded as strictly solitary albeit being the least studied of the extant Hyaenids. Accumulating evidence regarding the frequency of social interactions suggests a revision of striped hyena social structure is required. We hypothesized that striped hyena has a social structure that is more complex than expected for a strictly solitary species. For that end, we deployed an array of camera-traps in a remote desert region in Israel, and compared observed frequencies of striped hyena co-occurrence against null models to test whether hyena co-occurred more than expected by chance. Seven adults were (re)captured by our camera-traps in 49 different instances over 83 tracking days. Of these, 6 exhibited shared space-use around a scarce, isolated perennial water source. Five of them, co-occurred with other hyena (in 3 instances) significantly more frequent than expected by chance (and that timing suggests reproduction is unlikely to be the driving factor). Our findings substantiate evidence of complex social structure in striped hyena, highlight the importance of a scarce resource in space-use and sociality, and provide a baseline for future research of striped hyena social structure. We suggest that similar methods be employed to evaluate social structure in other "solitary species" to better understand their social dynamics.