A recent study compared the tooth wear between wild mandrills from our studied population in the Lékédi Park and yellow baboons living in the savannas of the Amboseli National Park (Kenya). The paper showed that, due to environmental and ecological differences between these two species, their levels of dental wear vary.
What is dental wear ?
Tooth wear is a loss of dental tissue (enamel, dentine) caused by the mechanical and chemical properties of the food, but also by the contact between teeth when occlusion occurs (particularly during the chewing process). This paper written by Jordi Galbany et al. focuses on the macrowear (visible to the naked eye). They scored the percent of dentine exposure on the occlusal surface of the teeth and found that, for a similar age, the percentage of dentine exposure varies between mandrills and yellow baboons. As you can see on the picture on the left, mandrill molars (A) are more worn than those of yellow baboons (B).
But why is this the case?
Ecological influences on tooth wear
The study finds two different factors that are most likely to influence tooth wear: the properties of the food and the composition of the soil the food grows in. Mandrills feed on various food items, some of which are hard-shelled fruit that have strong abrasive properties. In contrast, the yellow baboons mainly consume large amounts of underground storage organs that are not particularly hard to chew. Additionally, the soil in Lékédi Park contains higher amounts of quartz than the soil in Amboseli. This mineral is known to be hard enough to affect tooth wear and the animals get in contact with it in form of dust and grit on the fruit and roots they consume.
We can wonder if the important loss of enamel on wild mandrills molars result from an adaptative process to a more abrasive diet... We keep searching...
See also: Dental ecology blog
Galbany J, Romero A, Mayo-Alesón M, Itsoma F, Gamarra B, Pérez-Pérez A, Willaume E, Kappeler PM, Charpentier MJE. 2014. Age-related tooth wear differs between forest and savanna primates. PlosOne 9: e94938. [PDF]