Forage preferences and enrichment in a group of captive Livingstone's fruit bats Pteropus livingstonii

It has long been assumed that leaves constitute a very minor part of the di et of just a few Old World megachiropterans and New World phyllostomid bats , but this view is rapidly being undermined by increasing evidence of foliv ory in fruit bats. Leaves could be an essential factor in the ingestion of sufficient protein and nitrogen. Quite apart from the potential nutritional value of leaves to fruit bats, the behavioural enrichment value of present ing forage to them is significant. This study investigated this in a group of 11 Livingstone's fruit bats Pteropus livingstonii at Jersey Zoo, headqua rters of the Durrell Wildlife Conservation Trust, and assessed which plant species the bats preferred, with a view to providing a wider variety of for age items in the future. It is also important to take into account how the male dominance hierarchy affects access to food, and therefore the ranking system was also investigated. Four forage species were presented: willow, b amboo, ash and bramble. Willow and bamboo proved to be the most popular, bu t any species of forage was enough to stimulate the bats into activity. A s econdary effect of the increased activity in the group was an increase in a ggression, but considerable nonaggressive social interactions also took pla ce. The presentation of forage is therefore an effective enrichment activit y, but a possible associated increase in aggression should be borne in mind when designing forage presentation regimes.