Distribution of Palm Fruits on a Rain Forest Floor: Why White-Lipped Peccaries Forage near Objects

Abstract

Litter and soil disturbance in the wake of white-lipped peccary (Tayassu pecari) herds in southeastern Peru indicates that these animals often forage intensively at the bases of such as trees, exposed roots, logs, and lianas. I sampled the litter and soil near such objects on the forest floor, and found that fruits of the common palm trees were encountered more frequently near objects than in the open. This pattern was especially well marked for seeds of an Astrocaryum palm having a very restricted fruiting season. Where had recently foraged, densities of some fruit types were significantly reduced near objects. Apparently the peccaries are consuming palm fruits that have been scatterhoarded by rodents. WHITE-LIPPED PECCARIES (Tayassu pecari) occur in larger groups than any other terrestrial mammal in neotropical rain forests. Their herds, which may contain over 100 individuals, leave broad areas of overturned litter and disturbed soil wherever they have foraged. During a study of white-lippeds in southeastern Peru, I invariably noted that soil and litter disturbance in the wakes of herds was concentrated near certain objects-at the' bases of plant stems, along logs and exposed roots, and beneath lianas and low shrubs with dense foliage. One possible explanation for this observation was that the were searching for invertebrates in such places, as Ewer (1970) suggested to explain similar habits of the African forest hog Hylochoerus meinertzhageni. However, the extent of the disturbance seemed disproportionate to the small amounts of invertebrate body parts found in white-lipped stomachs (Kiltie 1980). Another possibility was that the peccaries were searching for fruits with hard endocarp at these places, since stomach contents, feeding experiments with captive animals, and anatomical evidence (Kiltie 1980) indicated that are distinguished by their ability to masticate very hard fruits and seeds. This explanation was further suggested by the fact that elsewhere in the neotropics, agoutis (Dasyprocta punctata) and squirrels (Sciurus granatensis) have been observed scatterhoarding fruits along tree bases, logs, roots, and beneath lianas (Smythe 1978: 26; Heaney and Thorington 1978; Morris 1962). Thus it was conceivable that were exploiting hard fruits that had been stored by rodents. The study described in this report was designed to see if palm fruits were more abundant near objects than elsewhere on the forest floor and to see if whitelipped peccaries were harvesting such fruits.