Introduction

Gorilla diet varies seasonally, geographically, and with altitude among eastern (Gorilla gorilla beringei and Gorilla gorilla graueri) and western (Gorilla gorilla gorilla) populations. Recent research on gorillas has highlighted the importance of fruit consumption and dietary flexibility at most sites (Rogers et al., 1990; Tutin et al., 1991, 1997; Remis, 1994, 1997a, b; Nishihara, 1995; Goldsmith, 1996, 1999 this volume; Doran and McNeilage, 1998; McFarland, 2000). Traditional characterizations of gorillas as folivores (Schaller, 1963; Fossey and Harcourt, 1977) have now shifted to include seasonal frugivory at all but the highest elevation sites (Yamagiwa et al., 1996; Remis, 1997a; Robbins, 2000). Nevertheless, gorillas have been argued to be opportunistic frugivores relative to the smaller and more persistently frugivorous chimpanzee (Nishihara, 1995; Kuroda et al., 1996), and some might characterize them as vacuum cleaners of the forest floor. I examine the consequences of large body size and habitat on dietary flexibility among gorillas as well as interpopulation variation in frugivory and nutrient intake. I further integrate research in captivity on taste sensitivity and food preferences with field data to explore some of the physiological and behavioral bases for dietary flexibility of gorillas in their native habitats.

Gorillas are most often described as herbivore–folivores, primarily as a consequence of their large size and spacious colons and cecums that contain a high number of cellulose-digesting ciliates (Collet et al., 1984).