Introduction
Outdoor enclosures for captive primates have become increasingly more common over the last 20 years, these more natural enclosures have been shown to significantly increase the behaviours observed by apes in captivity. These environments can stimulate more social and cognitive behaviour as well as allowing more physical activity (Hebert and Bard, 2002). For arboreal species such as Sumatran orangutans (Pongo abelii) and White-handed gibbons (Hylobates lar) there is a need for a complex environment, the enclosure needs to have sufficient vertical and horizontal structures that are connected by ropes or vines to help simulate the environment they would live in the wild. In order to improve current enclosures we must first understand…show more content… (2001) found that their studied gorillas went in 98% of their enclosure however over 50% of each individuals time was spent in <0.001 therefore providing evidence for both years that there is an association between the different apes and there preference for the structures in the outdoor enclosure. This allows us to reject our null hypothesis that there would be no association between the different apes and their preference for their outdoor structures. As both the years yielded similar results from a chi-squared test a Mann Whitney test was used to test the similarity of the observed results from each year. The results from the Mann Whitney produced a p value of 0.3067 therefore providing no statistically significant evidence for a difference to allow us to reject the null hypothesis. Therefore the results observed in 2014 and 2015 exhibited evidence that the apes had same preference for the structures in their…show more content… This is typical behaviour as in the wild gibbons need and use more space than other primates (Warren, 2010). In particular the males spent a major proportion of their time on the ground. This could be due to natural territorial behaviour but also the fact that George and Dagu are both sexually mature males, they sat in particular spots on the ground with Jiwa, sub-adult male moving about on the ground. This behaviour reflects that observed in the wild with dominant males having limited ranges in comparison to sub-adult males who range more (Singleton and van Schaik, 2002). But as the gibbons are fed outside on the ground in one area which was where George was mainly located we should conclude that he was mainly on the ground waiting and foraging for food. This is because they are fed on a predictable schedule and is displaying food-anticipatory behaviour (Bloomsmith and Lambeth, 1995). It was noted that the use of the high and medium structures by George and Hazel was mainly for sunbathing as the hide outside on the west island was at the top of a structure (recorded as a high structure). This is typical gibbon behaviour as they live in the tree canopy in the wild and spend their time mainly resting, foraging and travelling (Anderson,