Polo Biologico Integrato, C.N.R., Roma, Italy
The well-being of captive nonhuman primates is fostered by living in complex environments and by having a certain degree of control over it. There are many different techniques that can be used to achieve this goal. For example, we can provide the animals with foraging opportunities which increase the time spent to search and consume the daily ration of food. Biological and behavioral differences among species and among individuals deserve to be taken into account when designing the best approach. We should measure animal's responses to a device before offering it as a permanent enrichment device, and evaluate whether it is beneficial.
In this study we wanted to assess the responses of two groups of tufted capuchin monkeys (N=11) to a 30 cm x 25 cm feeding board. The board consisted of a metal support to which plastic blades of grass were securely fastened; 9-100 g wheat seeds were scattered inside the plastic blades of grass. The feeding-board was alternatively positioned on the upper level of the cage (165 cm above the floor) or on the lower level of the cage (10 cm) in order to assess whether the monkeys showed any spatial preference. Each group was observed for a total of 16 30-min sessions. The attractiveness of the enrichment device was estimated by calculating the percentage of time in which the individuals were searching or picking food.
Results show that the feeding-board were almost always in use. In 97.3% (group 1) and in 98% (group 2) of the intervals at least one individual was by it searching and picking food. These behaviors were shown by all individuals, but to a different extent (values ranging between 76% and 6%). In both groups, in 80% of the intervals there were more than one individual (in most of the cases 2 or 3) using simultaneously the feeding-board.
There was no evidence that the position in which the feeding board was placed influenced its use. However, some individuals showed spatial preferences.
This article originally appeared in Primate Report 42: 23-24 (1995).
Reprinted with permission of the Editor.