There is a growing need for non-human primate populations in captivity to be managed using techniques based on scientific principles, so as to be able to maintain self-sustaining populations and also, if need be, successfully reintroduce these populations into their wild habitats. It is thus recognised that captive primate groups should be housed in environments in which their welfare is not compromised where they can exhibit most, if not all, of their natural social and behavioural characteristics. In order to design and maintain ideal captive environments for primates, it is important to incorporate applied animal behaviour and welfare research in the mandateo f conservationb reedingp rogrammesin zoos. In this study, the behaviour of captive lion-tailed macaquesin 18 Indian zoos was recorded to identify the factors that influence the behavioural repertoire of captive lion-tailed macaques. 'Me first step was to construct a detailed ethogram; behavioural observations were then conductedu sing ad libitum sampling,f ocal animal samplinga nd instantaneouss cans. Sampling was carried out only during the day when visitors were present at the macaque enclosures. The results showed that stereotypic pacing was the most commonly exhibited behavioural. abnormality. Abnormal behaviours were only exhibited by confiscated and zoo-bom individuals but never by wild-caught and captive-reared animals. Active foraging behaviours were influenced by enclosure complexity. In order to determine what improvfments could be made to the zoo enclosures, two behavioural studies were conducted on six singly-housed captive lion-tailed macaquesi n ThiruvananthapurarnZ oo. In Study A, cotton ropes and a feeding basket were added to the enclosures and were later removed, while in Study B, the singly-housed individuals were transferred to a large open-moated enclosure in which they were group-housedI.n Study A, frequenciesa nd proportions of abnormal behaviour exhibited differed significantly across the five phases of the study with the lowest proportions being exhibited when the macaquesw ere fed in elevate d f eedi ng baskets. During this phase, frequencies of exploratory behaviours and other natural behaviours also increased. Self-biting exhibited by several of the singly-housed macaques appeared to be redirected towards the enrichment provided, thus reducing the overall levels of abnormal behaviour exhibited. In Study B, the six captive lion-tailed macaques exhibited significantly greater levels of abnormal behaviour when they were housed singly in barren cages. Individuals exhibited higher levels of active foraging when they were in group-housed in the open-moated enclosure. A further study was conductedt o investigatet he influence of visitors' presenceo n captive liontailed macaquesT. he behayioural study was conductedo n 35 individuals housed in 10 zoos across India. The study animals were observed on days with visitors present and on zoo holidays when there were no visitors. To record the long-term impact of visitors' presence on captive primate behaviour and welfare, another study following the same sampling method was conducted in which the behaviour of seven singlyhoused individuals was recorded independently in 'on-exhibit' and 'off-exhibit' enclosures of similar sizes. Captive macaques exhibited lower levels of abnormal behaviour on zoo holidays and the frequency of begging when off-exhibit was lower as compared to days with visitors present and in on-exhibit enclosures respectively. Even social behaviour was influenced by visitors' presence, with captive lion-tailed macaques exhibiting both higher proportion of time spent in social behaviour and higher frequencies of reproductive behaviour on zoo holidays. In conclusion, the presence of visitors, enclosure design, group composition and early rearing history were all found to influence the behaviour and welfare of captive lion-tailed macaques in the study zoos. Enriching the enclosures and changing the social circumstances of the macaques were found to positively influence the welfare of the study animals, because they led to them exhibiting more natural behaviours. Indicators that were most suitable in assessingt he welfare of captive lion-tailed macaquesi ncluded the physical-condition factor and the developmental and reproductive success factor accounting for the highest proportion of the total variance in the population. These factors were 'non-invasive' and 'hands-off and hence proved ideal for assessing the welfare of individuals that were part of a conservation breeding programme.