The effects of dental impairment on the biology and behavioral ecology of wild ring-tailed lemurs (Lemur catta) at the Beza Mahafaly Special Reserve, Madagascar

Ring-tailed lemurs (Lemur catta) of the Beza Mahafaly Special Reserve (BMSR) demonstrate exceptionally high rates of dental wear and subsequent tooth loss due to tamarind fruit consumption. How such wear and loss affects their behavior, nutrition and health is not yet fully understood. This study examines how dental impairment impacts ring-tailed lemur biology and behavioral ecology through a broad dental-ecological framework involving use of topographic analyses of tooth form, food processing data collection, and fecal measures of nutritional status. This study also presents visual measures of coat and body condition applicable to dental studies. Increasing topographically-measured dental impairment was associated with longer tamarind fruit feeding times and increased use of alternative tamarind fruit processing techniques (e.g., use of open fruit, manual processing and toothrow use). Increasing impairment was also associated with longer bouts for variety of other food types and species, although several foods were associated with shorter bouts, suggesting that food mechanical properties play a role in the expression of behaviors relative to dental impairment. Individuals with tooth loss and wear demonstrate larger particles within their fecal material, suggesting they possess a reduced capacity to digest and absorb ingested foods. This hypothesis was supported by fecal-nutritional analyses indicating that impairment often reduces individual capacity to ferment structural carbohydrates and/or results in seasonally increased residual fecal protein. Dental impairment was also associated with higher fecal ash content, suggesting that tooth wear at this site may also be a function of dietary silicates in addition to that caused by tamarind fruit feeding. Measures of coat and body condition indicate that lemurs show increased coat quality following the onset of the wet season when resource availability increases, and that body size appears to be related to reproductive status. As these are measures that appear to be linked to energetic status, their use may also be beneficial in future studies of dental impairment. Overall, data from this study indicate that dental impairment has real, significant and typically negative impacts on BMSR ring-tailed lemurs in terms of their feeding behaviors, ability to process foods and their capacity to utilize ingested resources.