Four studies were conducted to investigate behavioural and physiological indicators of welfare in western lowland gorillas (<i>Gorilla gorilla gorilla</i>) 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.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:604049 |
| Date | January 2005 |
| Creators | Hill, S. P. |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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