Efecte de l'enriquiment i el sexe biològic sobre la conducta de ximpanzès (Pan troglodytes) en captivitat

Abstract

The chimpanzee (Pan troglodytes) is a primate species that is currently endangered. In the wild,

they live in open communities divided into small groups of males and females with different

hierarchical ranks, and over time they regroup, following a fission-fusion social system. The

search for and acquisition of food in their natural habitat occupies a large part of their daily life,

which does not happen when they are in captivity, as they are provided with food directly and in

a more or less unlimited manner. This situation causes captive chimpanzees to stop exhibiting

behaviors commonly seen in the wild and, instead, to exhibit abnormal behaviors that do not

manifest under natural conditions. To minimize the negative effects that can appear in captive

animals and out of concern for their welfare, enrichment is used to ensure that individuals in

captivity spend a good part of their daily activity obtaining food and exhibit natural behaviors as

they do in the wild.

In this study, an evaluation was made of the relationship between the use of enrichment and the

behavior of two groups of captive chimpanzees located at the Centre de recuperació de primats

de la Fundació Mona, and the possible existence of differences between biological sexes in

relation to enrichment was assessed. The results showed that the presence of enrichment has direct

effects on the behavior of the individuals, increasing behaviors such as grooming, manipulation

of enrichment items, and play activity, and decreasing agonistic behaviors. However,

unexpectedly, no relationship was found between the presence of enrichment and abnormal,

affiliative (except grooming), or inactive behaviors. Additionally, it was found that playful

activities such as object manipulation and solitary play are more frequent in females than in males,

which agrees with the expected results.

The differences between groups regarding grooming behavior may be due to the consolidation of

the Mutamba group, while the Bilinga group, less consolidated, spends more time on solitary

activities such as object manipulation. Significant differences were found only in relation to the

sex of the individuals in playful behavior, with females using enrichment more. The presence of

enrichment increases grooming and reduces agonistic behaviors, especially with complex mobile

enrichment, which prevents monopolization and promotes cognitive activity to obtain food.

Therefore, it is concluded that enrichment has a positive impact on the behavior of chimpanzees,

suggesting the need for continued research to improve their mental health and welfare