Tooth fracture within the African carnivore guild: the influence of intraguild competition and resource availability

Although tooth fracture may have severe energetic and behavioural implications for carnivores, it occurs commonly, perhaps as a result of a high risk diet and lifestyle. To investigate the influence of intraguild competition and resource availability, tooth fracture was quantified in 10 African carnivores (N=851), which occur sympatrically across several aridity zones (i.e., a resource gradient). Tooth fracture incidence was compared across principal components representing temperature and precipitation, as well as the number of carnivores >21kg present and factors previously considered influential. Multimodel inference was used to determine the relative influence of factors. Ecomorphological factors (e.g., degree of carnivory) and tooth wear (a product of age and diet) were considered most influential, whilst tooth fracture incidence did not vary between sexes. Precipitation, which is known to affect primary production and herbivore biomass, was more influential than temperature, with fewer tooth fractures in wild dogs and leopards where precipitation availability was higher. Competition was the most influential factor for wild dogs, with higher tooth fracture incidence where more carnivores were present, corresponding with a previous study that shows relative predator abundance to be more influential than prey numbers for carcass consumption - the likely cause of tooth fracture. However, leopards and black-backed jackals exhibited lower tooth fracture incidence where more carnivores were present, perhaps because of a positive association between competition and precipitation, or changes in prey preferences where carnivore abundance is high. Relative prey and predator biomass may provide better proxies for resource availability and intraguild competition in future studies and long-term studies of predation may provide insight into factors affecting carcass consumption. An understanding of the influences of guild richness and resource availability is important for modern systems that are currently undergoing changes in competitive dynamics, where carnivores occupy the vulnerable position of apex predators.