Green-Leaf Fractionation by Fruit Bats: Is This Feeding Behaviour a Unique Nutritional Strategy for Herbivores?

Abstract

The black fruit bat, Pteropus alecto, feeds on Albizia lebbek by chewing leaves to a bolus, swallowing the liquid fraction, and expelling the pellet of fibrous residue from its mouth. The extract contains about 51% of the crude protein of the leaf which has about 36% protein. This feeding behaviour occurs widely among Old World megachiropterans but is rarely seen, probably because very few tropical trees can be used in this way. As a herbivore nutritional strategy this process of green-leaf fractionation appears to be unique, but it is suggested that it may be used by some arboreal primates. The strategy represents an extreme way in which leaf material can be handled in the herbivore digestive tract; rather than dealing with leaf fibre, it is avoided altogether.