Change of enclosure in langur monkeys: implications for the evaluation of environmental enrichment

Abstract

Abstract A group of Hanuman langurs ( Presbytis entellus ) was studied before and after it was moved from an old cage‐style enclosure to a novel naturalistic environment at the London Zoo. Eating and locomotion occupied more of the langurs' time in their new enclosure, whereas dozing, allogrooming, and aggression decreased, along with an increase in inter‐individual distances. These changes are attributed to the larger area, the stimulating new environment, and the langurs' increased distance from visitors. Nevertheless, the study raises questions about how to define standards of desirable environmental enrichment, as the activity patterns recorded in both the old and new enclosures are within the variation observed in the wild. Zoo Biol 21:549–559, 2002. © 2002 Wiley‐Liss, Inc.