Abstract
Tooth wear in primates is caused by aging and ecological factors. However, comparative data that would allow us to delineate the contribution of each of these factors are lacking. Here, we contrast age-dependent molar tooth wear by scoring percent of dentine exposure (PDE) in two wild African primate populations from Gabonese forest and Kenyan savanna habitats. We found that forest-dwelling mandrills exhibited significantly higher PDE with age than savanna yellow baboons. Mandrills mainly feed on large tough food items, such as hard-shell fruits, and inhabit an ecosystem with a high presence of mineral quartz. By contrast, baboons consume large amounts of exogenous grit that adheres to underground storage organs but the proportion of quartz in the soils where baboons live is low. Our results support the hypothesis that not only age but also physical food properties and soil composition, particularly quartz richness, are factors that significantly impact tooth wear. We further propose that the accelerated dental wear in mandrills resulting in flatter molars with old age may represent an adaptation to process hard food items present in their environment.
Highlights
Tooth morphology and enamel microstructure are linked to the mechanical properties of ingested food [1,2,3,4,5,6], and the effects of dental wear can be seen in occlusal surface morphology in particular [7]
In order to determine whether the environment and feeding ecology are related to tooth wear variability in primates, we examine here the relationship between tooth wear and age in two African papionins, the forest-dwelling mandrills (Mandrillus sphinx) and the savanna-living yellow baboons (Papio cynocephalus) that show contrasting feeding behavior
Results from linear regressions between percent of dentine exposure (PDE) and age were complemented with an overall multivariate analysis of variance (MANOVA) to detect changes with age for each molar tooth in both species and analysis of covariance (ANCOVA) to test for the homogeneity of slopes between species, sex and origin in the case of mandrills
Summary
Tooth morphology and enamel microstructure are linked to the mechanical properties of ingested food [1,2,3,4,5,6], and the effects of dental wear can be seen in occlusal surface morphology in particular [7]. In experimental studies on vervet monkeys (Chlorocebus aethiops) using controlled diet, animals which feed on more abrasive food items present greater average annual tooth wear [15]. Studies on 3D dental topography in wild howler monkeys (Alouatta palliata) [17], sifakas (Propithecus edwardsi) [10] and mountain gorillas (Gorilla beringei beringei) [18] show that tooth wear increases with age, and changes in molar crown occlusal morphology affect the occlusal surface slope and relief as wear progresses. The fact that age seems not to greatly impact shearing capacity in these two species suggests that natural selection may shape tooth anatomy to maintain a certain degree of occlusal relief and functionality, especially in those folivorous primates that may need higher cusps for a lifelong mastication of tough fibrous foods [10,18]. Some researchers have suggested that primate teeth have retained functionality after moderate wear, even improving it to a degree [19]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
