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Title: Behavioural and physiological investigations of welfare in captive western lowland gorillas
Author: Hill, S. P.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2005
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Four studies were conducted to investigate behavioural and physiological indicators of welfare in western lowland gorillas (Gorilla gorilla gorilla) housed at six European zoos. In the first two studies, behavioural responses of gorillas to changes in housing were measured, namely relocations to new enclosures (Study 1) and feeding-related environmental enrichment efforts (Study 2). As enrichment efforts do not necessarily equate with successful enrichment, I hypothesised that these housing changes would have either an enriching, aversive or neutral effect on animals. The results of Study 1 have shown that the behavioural repertoire of most individuals did not change across the entire post-relocation period compared with the baseline. Greater behavioural responses were observed month-by-month and, for some individuals, conclusions can be drawn about changes in welfare. In Study 2, behavioural data were collected before, during and after the provision of feeding-related environmental enrichment efforts designed to provide a more complex feeding environment. For most individuals, these efforts were associated with a reduction in time spent performing behaviours that indicate poorer welfare, compared with during the baseline. Faecal samples collected opportunistically during Studies 1 and 2 were used in Study 3 for glucocorticoid metabolite analyses. The results of a validation procedure showed that an enzyme immunoassay (EIA) measuring 5β-3α,11β-diol corticoid metabolites was likely to have practical applications for this purpose . Gorillas’ adrenal responses to the housing changes suggested that there has been an enriching effect overall. Results of a storage experiment showed that faecal samples can be left at environmental temperature (25 °C) for up to 8 hours after defecation with no significant effect of bacterial enzymes on metabolite concentrations.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available