Age and individual foraging behavior predict tooth wear in Amboseli baboons

Abstract

Teeth represent an essential component of the foraging apparatus for any mammal, and tooth wear can have significant implications for survival and reproduction. This study focuses on tooth wear in wild baboons in Amboseli, southern Kenya. We obtained mandibular and maxillary tooth impressions from 95 baboons and analyzed digital images of replicas made from these impressions. We measured tooth wear as the percent dentine exposure (PDE, the percent of the occlusal surface on which dentine was exposed), and we examined the relationship of PDE to age, behavior, and life history variables. We found that PDE increased significantly with age for both sexes in all three molar types. In females, we also tested the hypotheses that long-term patterns of feeding behavior, social dominance rank, and one measure of maternal investment (the cumulative number of months that a female had dependent infants during her lifetime) would predict tooth wear when we controlled for age. The hypothesis that feeding behavior predicted tooth wear was supported. The percent of feeding time spent consuming grass corms predicted PDE when controlling for age. However, PDE was not associated with social dominance rank or maternal investment. Am J Phys Anthropol 000:000-000, 2010. Keywords aging; feeding behavior; foraging; Papio cynocephalusTeeth represent an essential component of the foraging apparatus for any mammal and tooth wear can have significant implications for survival and reproduction (Lanyon and Sanson, 1986;Buss, 1990;Logan and Sanson, 2002;Hillson, 2005;King et al., 2005;Veiberg et al., 2007). Data from a number of mammal species provide evidence for the adaptive importance of teeth, the functional significance of tooth wear, and the relationship between tooth wear and age. For instance, rodents have ever growing incisors and their foraging behavior results in constant wearing and sharpening, which in turn results in the teeth being kept at a constant height in the jaw throughout life (Hillson, 2005). Further, Williams and Kay (2001) found that rodent species adapted to more abrasive diets, such as grass, had relatively higher molar crowns than other rodents. Among roe deer, those with larger teeth (Veiberg et al., 2007). Elephants provide another example. After the sixth set of teeth is worn to a point about half its original height, the animal can no longer masticate food adequately; thus elephants rarely live beyond this stage of tooth wear (Buss, 1990). Tooth wear also has been related to individual fitness in one study of primates. King et al., (2005) found that in sifakas (Propithecus edwardsi), older females lost their infants at higher rates than younger females. They argued that tooth wear in older females was likely to be an important factor in this relationship. One attempt to replicate this study in another species (deer) failed to find an effect of tooth wear on infant survival (Nussey et al., 2007). Nonetheless, these examples highlight the importance of having functional teeth in mammals and even connect l...

The Hadropithecus conundrum reconsidered, with implications for interpreting diet in fossil hominins

“…One possibility is that Hadropithecus ate underground storage organs (USOs) of C 4 plants (see also [20]). Hadropithecus lived in environments in which the bulbs and corms of grasses and sedges could have sustained it through the portions of the year when the leaves turn brown and lose their nutrient content-much in the way that Amboseli baboons (Papio cynocephalus) spend up to 70 per cent of their time foraging on the small USOs of grasses [37,38]. The consumption of large quantities of bulbs and corms compensates for their…”

Tooth Size Variation Related to Age in Amboseli Baboons

“…A number of studies have also examined the effect of aging on tooth functionality and the consequent effects of aging teeth on the fitness of individuals or populations [Cuozzo and Sauther, 2010]. Many studies show that occlusal tooth wear reflects age in wild primates (sifakas [King et al, 2005;Wright et al, 2008]; howler monkeys [Dennis et al, 2004]; baboons [Phillips-Conroy et al, 2001;Galbany et al, 2011]; lemurs [Zohdy et al, 2009;Cuozzo and Sauther, 2010]) and semi-captive primates (rhesus macaques [Kay and Cant, 1988]). Moreover, occlusal tooth wear in Amboseli baboons was also predicted by individual differences in feeding behavior [Galbany et al, 2011].…”

First molar size and wear within and among modern hunter-gatherers and agricultural populations

“…The area of dentin exposure was measured in the same way (Fig. 1), outlining the dentin exposure areas, visible as depressed surfaces in the dental replicas (Galbany et al, 2011). If several spots of dentin exposure were present in one tooth, each was measured separately and the sum of all the areas was calculated as area of dentin exposure (ADE) and used in further analyses.…”