Costs of carnivory: tooth fracture in Pleistocene and Recent carnivorans

Abstract

Large, carnivorous mammals often break their teeth, probably as a result of tooth to bone contact that occurs when carcasses are consumed more fully, a behaviour likely to occur under conditions of food stress. Recent studies of Pleistocene predators revealed high numbers of teeth broken in life, suggesting that carcass utilization and, consequently, food competition was more intense in the past than at present. However, the putative association between diet and tooth fracture frequency was based on a small sample of large, highly carnivorous species. In the present study, a greater diversity of extant carnivorans is sampled, including insectivorous, omnivorous, and carnivorous forms, ranging in size from weasels to tigers. Species that habitually consume hard foods (bones, shells) had the highest fracture frequencies, followed by carnivores, and then insectivorous and/or omnivorous species. Predator and prey sizes were not associated with tooth fracture frequency, but more aggressive species did break their teeth more often. Comparison of the modern sample with five Pleistocene species confirms the previous finding of higher tooth breakage in the past, although some extant species have fracture frequencies that approach those of extinct species. Thus, the Pleistocene predator guild appears to have been characterized by relatively high levels of competition that are rarely observed today. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 68–81.

Cranial morphometrics of the dire wolf, Canis dirus, at Rancho La Brea: temporal variability and its links to nutrient stress and climate

“…Increased bone consumption is associated with nutrient stress because carcasses are consumed more completely when prey are difficult to acquire, due to primary productivity reductions and/or an increase in intra-and interspecific competition. Large-bodied, North American Pleistocene carnivores, such as dire wolves, sabertooth cats, and lions, all had significantly elevated rates of tooth fracture relative to their modern counterparts, suggesting a greater intensity of interspecific competition in Pleistocene communities (Van Valkenburgh, 2009;Meloro, 2012). At Rancho La Brea, dire wolves exhibit fracture frequencies that vary significantly over time, suggesting fluctuating levels of food stress.…”

“…Another aspect of temporal biotic variation quantified at Rancho La Brea is the rate of tooth fracture and wear in large carnivores (Van Valkenburgh and Hertel, 1993;Binder et al, 2002;Binder and VanValkenburgh, 2010). Tooth fracture frequency is positively correlated with tooth wear, and both are associated with higher rates of bone consumption in terrestrial carnivorans, both among and within species (Van Valkenburgh, 1988, 2009Meloro, 2012). Increased bone consumption is associated with nutrient stress because carcasses are consumed more completely when prey are difficult to acquire, due to primary productivity reductions and/or an increase in intra-and interspecific competition.…”

The impact of large terrestrial carnivores on Pleistocene ecosystems

“…Larger groups in turn would favor more complete consumption of carcasses, including bones. Among modern carnivores, more bone is eaten when prey are more difficult to acquire, and this activity increases both the number of teeth broken in life and rates of tooth wear (38). Elevated tooth fracture frequencies observed among multiple species of Pleistocene carnivores suggest ecosystems in which the densities of predators relative to prey were high, and thus competition for carcasses was intense, leading to more frequent intra-and interspecific confrontations over kills (39).…”

“…Elevated tooth fracture frequencies observed among multiple species of Pleistocene carnivores suggest ecosystems in which the densities of predators relative to prey were high, and thus competition for carcasses was intense, leading to more frequent intra-and interspecific confrontations over kills (39). In large New World predators of the Pleistocene, for example, rates of tooth fracture are as much as three to five times that of their modern counterparts (38). Very high rates of tooth fracture are also present in Pleistocene gray wolves from Great Britain dated between 50 and 85 thousand years ago (40) and late Pleistocene cave lions and cave hyenas from Zoolithen Cave, Germany (our data, SI Appendix, Table S4).…”

The Wear and Tear of Teeth

“…Evidence for the effect of larger-scale crown fractures, such as wholesale cuspal fractures [18,19,20,21],enamel chipping [22,23,24,25] and the splitting of tooth crowns in half [25], are less well known, but there is no doubt that ingestion and mastication are impaired. The effect is not the same on modern human populations because of ubiquitous pre-ingestive processing and cooking of foods.…”