Nutrient composition of selected plant species consumed by semi free-ranging lion-tailed macaques (Macaca silenus) and ring-tailed lemurs (Lemur catta) on St. Catherines Island, Georgia, USA

Feeding behavior in two groups of semi free-ranging primates, lion tailed m acaques (LTM) (Macaca silenus, n = 9) and ring-tailed lemurs (RTL) (Lemur c atta, n = 13), residing on St. Catherines Island, GA, was observed seasonal ly at quarterly intervals for 1 year. Each group had unlimited access to na tive flora and fauna in addition to a daily provisioned diet; LTM were obse rved a total of 144 hours and RTL for 208 hours. We hypothesized that foods selected by macaques would be lower in macronutrients and higher in fiber than those consumed by lemurs owing to body size differences. Samples of pl ant foods observed eaten (106 samples from 30 identified species) were coll ected, air-dried in the field, and analyzed for macronutrient, fiber, and m ineral content. Leaves and seeds were important diet components for semi fr ee-ranging LTM most of the year, comprising 51% to 93% of observed feeding time on nonprovisioned food items, with ripe fruit a major food item (40% o f observed feeding time) only during the August sampling period. In general , RTL consumed a more diverse diet of fruits and leaves during all seasons, with seeds and buds increasingly important during winter months (45% of ob served feeding time). Based on the nutrient composition of different plant parts, weighted by the percentage contribution (feeding time assumed equiva lent to mass of forage intake) of each part, no difference was seen in fibe r (LTM 56.8 +/- 21.9% of DM, RTL 38.4 +/- 16.7% DM) or crude protein conten t of diets consumed (LTM 9.0 +/- 2.9% DM, RTL 11.5 +/- 6.7% DM) throughout the year. Weighted diets contained mineral concentrations meeting recommend ed values for non-human primates of Mg, Cu, Mn, and Zn, but were low in Na, P, and Fe, as well as Ca (LTM only). Despite wide differences in individua l food items selected, overall diets were remarkably similar in macronutrie nt composition between these two disparate primates. (C) 1999 Wiley-Liss, I nc.