The effects of zoo visitors on a group of Western lowland gorillas Gorilla gorilla gorilla before and after the birth of an infant at Dublin Zoo

Abstract

Increasingly, it is understood that one must take into consideration all aspects of the zoo environment when assessing visitor effects. One of the unexplored topics in this area is the impact of a new group member in combination with the visitor effect on primates. Here, we investigate the effect visitors have on a group of Western lowland gorillas Gorilla gorilla gorilla before and after the birth of an infant. Observational data were obtained through scan sampling before and after the infant's birth and during different visitor conditions. Results indicate that the birth of the infant lessened some of the negative visitor effects previously observed in this group of gorillas. Particularly when in the ‘high’ visitor numbers category, the adult ♂ foraged more, was less inactive and more social after the infant's birth than he had been before. However, certain negative behaviours associated with increased visitor number, such as aggression and ‘back to viewing window’, were not diminished with the birth of the infant. Although results varied between individuals, there are indications that an event such as the birth of an infant may lessen negative visitor effects.