Food procurement and tooth use in two sympatric lemur species.

This study of two lemur species (Lemur catta and Propithecus v. verreauxi) in Madagascar combines observations of food procurement and initial food placement in the mouth with comparisons to food toughness and external properties. Food toughness was hypothesized to play a decisive role in determining food placement during ingestion. It was found that tougher foods are generally ingested on the postcanines for all foods eaten. However, when leaves and fruits are analyzed separately, food size and shape, represented here by mass and food type, are more reliable predictors of initial food placement. Larger leaves and bulkier fruits and stalks are ingested posteriorly. Leaf toughness is not related to leaf size, though the toughness and size of the most commonly eaten fruits are correlated. Furthermore, ingestive food toughness, which is the maximum toughness, and "average" food toughness may make different mechanical demands on the masticatory apparatus that have consequences for jaw morphology.