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Title: Investigation of the inter-specific interactions between silver leaf langurs and Asian short-clawed otters
Author: Rosalie Dench
Establishment: Cambridge University
Summary: The aim of this study was to assess and monitor interactions between Asian short clawed otters and silver leafed langurs which were moved into a mixed species exhibit on 24th March 2006. The hypotheses tested were that the associations occurred no more frequently than by chance and that when associations do occur they are associated with defence of limited resources such as food, shade, and enrichment substrate or shared responses to a perceived threat. The first hypothesis was tested by recording enclosure use and the second by studying the behavioural repertoire, nearest neighbour identification and interactions. Three data collection periods were conducted in September 2006, December 2006 and March 2007. Group scan sampling was carried out at 3 minute intervals during hour long observation slots, 5 slots were spaced throughout the day. Each scan recorded all animals seen, behaviour, location, minimum estimated distance between heterospecifics and also between conspecifics. Ad libitum sampling was also used to record occurrences of heterospecific behaviours and visitor numbers and weather were also recorded for future comparisons. A pilot study was conducted to test methods and identify behaviours and in total, 30 hours of observations were carried out during each collection period, amounting to 90 hours of observations with 20 scan samples per hour.
Complete article:
Data recorded to test for hypothesis one, that the associations occurred no more frequently than by chance, were significant, suggesting that the otters significantly avoided areas occupied by the langurs, but that the langurs actively spent time in the otters’ territory when the otters were present compared to when they were out of sight. This pattern was interesting, suggesting the otters may be maintaining distance from the langurs, while the langurs may be seeking out associations with the otters.
Data recorded to test for hypothesis two, that when associations do occur they are associated with defence of limited resources or shared responses to a perceived threat, suggested that although competition for preferred resources may be occurring, it was not a major cause of interactions during this study.
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