Naturally-occurring tooth wear, tooth fracture, and cranial injuries in large carnivores from Zambia

Abstract

Determining the incidence and causes of craniodental damage in wild carnivores is often constrained by limited access to specimens with associated ecological data, such as prey type and abundance. We assessed dental condition and cranial injuries in lion, leopard, and spotted hyena in relation to prey and predator populations in Zambia’s Luangwa Valley, where large prey are more abundant and lion and leopard more numerous, and the Greater Kafue Ecosystem, where smaller prey species are more prevalent and lion and leopard less common. In Luangwa, lions had significantly higher rates of tooth fracture, and blunt trauma injuries attributable to prey-handling, compared to Kafue lions. In contrast, leopards in both regions had similar rates of tooth wear and breakage. Overall, lions showed a significantly higher tooth fracture rate than leopards on a per tooth basis. Spotted hyenas had the highest rates of tooth wear and fracture among all three carnivores, and greatly exceeded previously recorded rates based on historical samples. Despite larger numbers of lion and leopard in Luangwa, there was no difference in incidence of intraspecific injuries between regions. These results are consistent with a greater abundance of large prey species, especially buffalo, in the diets of Luangwa lions, and previous work showing a reliance on smaller prey species in Kafue throughout the large carnivore guild.

Low-Cost Forensics Reveal High Rates of Non-lethal Snaring and Shotgun Injuries in Zambia's Large Carnivores

“…For each skull examined, we recorded incidents of the diagnostic tooth damage that results from repeated biting and pulling on a wire snare, most notably abnormal V-shaped horizontal notches on the posterior edge of the upper and lower canines (Figure 2). This pattern of tooth damage differs markedly from natural tooth wear that occurs with age in these species (lion- Smuts et al, 1978;Whitman and Packer, 2007;leopard-Stander, 1997) and that was described previously for this same sample of specimens (Van Valkenburgh and White, 2021). The severity of tooth damage likely depends on physical aspects of the snare itself, such as wire gauge, where on the body the animal was snared, how long the snare was in place, and whether the animal was able to reach the wire to bite and pull on it.…”

“…In Van Valkenburgh and White (2021), we reported on naturally-occurring tooth wear, tooth breakage, and cranial injuries in trophy-hunted carnivores. We proposed that standardized photographs of the skulls and teeth of hunted carnivores be required to be collected and archived for purposes of scientific investigations and population-level comparisons of carnivore health.…”

“…Old shotgun pellet injuries were identified by the presence of pellets visibly embedded in the skull, shallow circular indentations containing evidence of pellet fragments, metal marks, and resultant bony inflammation (Figure 4). The presence of fragmented pellets, metal marks, and inflammation are directly associated with lead pellets (as opposed to steel or copper), and make shotgun pellet injuries easily discernible from naturally-occurring injuries attributable to prey-handling and intraspecific conflict (Van Valkenburgh and White, 2021). Damage to skulls that was associated with time of death was readily determined (e.g., gunshot wound with unhealed splintered bone) and excluded from analyses.…”

“…Here, we present a new method for determining an individual's history of snare entanglement that relies on diagnostic tooth wear that differs markedly from natural tooth wear (Van Valkenburgh and White, 2021). Carnivores often use their teeth to bite or pull on the wire when attempting to free themselves from a snare, and can damage their teeth in the process.…”

Performance of wild animals with “broken” traits: Movement patterns in nature of moose with leg injuries

“…Injuries to some of these hard structures are well documented as they leave lasting signatures evident even long after death. Studies of structural injuries include birds that break their beaks (Slevin et al, 2016 ) and carnivores that break their teeth (Van Valkenburgh & White, 2021 ). Further, animals can break any number of bones (Stephens et al, 2018 ; Woodman, 2013 ), such as by falling from trees or cliffs or via damage from predators or humans (e.g., bullets, cars, traps, snares) or human structures (e.g., cattle guards).…”