Stereotypic route tracing in captive Carnivora is predicted by species-typical home range sizes and hunting styles

In captive conditions (e.g. zoos), some Carnivora species typically show negligible stereotypic behaviour (SB) and reproduce successfully, while others tend to reproduce poorly and be very stereotypic. We used comparative methods to identify species level risk factors for SB and captive infant mortality (CIM). Candidate predictor variables were natural ranging behaviour, territoriality, aspects of natural foraging, wild activity levels, cranial volume and IUCN Red List status. Previous research had identified naturally long daily travel distances and being large-bodied and wide ranging as SB risk factors. We nearly doubled the size of this original SB database, and then imposed stricter quality controls (e.g. on minimum sample sizes for inclusion). Analysing the resulting 23 species data set confirmed naturally large ranges and travel distances as risk factors. It also showed that the range size effect is independent of body mass (although body mass and range size together predicted SB most strongly), is stronger for stereotypic route tracing (e.g. pacing) than for all SB forms combined, and explains the apparent daily travel distance effect (which vanished when range size was controlled for). Furthermore, naturally long chase distances during hunts now also predicted more severe route tracing. Previous research had also identified naturally long travel distances and large home ranges as risk factors for CIM. We failed to replicate this, or to confidently identify any species level risk factor (despite CIM significantly varying between related species, at least for Canidae and Ursidae). Understanding what underlies high species-typical CIM thus requires more data and further research. Overall, naturally wide-ranging Carnivora with long chase distances are thus most prone to extensive stereotypic route tracing in captivity. This suggests that captive carnivores cannot relinquish aspects of ranging and pursuit hunting, even when their homeostatic needs are met, and also suggests new strategies for environmentally enriching their enclosures more effectively.