Cotton – Top Tamarins (Saguinus oedipus) are small, diurnal New World monkey that can be found in north-western Columbia and are classified as critically endangered species. This species is frequently housed in ZOOs, including Tropska hiša in Celje. In the thesis we were interested whether different coloured enrichment objects affect behaviour withing the group of Cotton – Top Tamarins. Through behavioural analysis, we wanted to find out which of the objects is most suitable for these animals. We investigated the influence of green and red colour of the enrichment object on the performance of active and social behaviours among specimens.
We recorded a group of tamarins for one hour at the same time for three days in a row. We recorded the animals for half an hour before and half an hour after exposure to enrichment objects. We used three nutritional enrichment items of the same shapes but different colours: unpainted, red and green. We analysed the clips using the BORIS program and calculated the frequencies and durations of the observed behaviours. We had previously categorized the behaviours into active, inactive, social behaviours, and behaviours related to enrichment objects, and described them in an ethogram.
We assumed that the presence of a green enrichment object would increase the frequency and duration of active behaviours and decrease the frequency and duration of social behaviours. In addition, we assumed that the red enrichment object would decrease the frequency and duration of active behaviours and increase the frequency and duration of social behaviours. Based on previous research, we also assumed that, among all objects, the green enrichment object would be engaged with for the longest duration.
We found that all enrichment objects used were effective in promoting the active behaviours and reduced the presence of social behaviours, with no differences between the objects of different colours used. Thus, we could not confirm the influence of object colour on the animal behaviour. Most likely, the shape of the enrichment object itself had a greatest influence, as it increased the occurrence of active (individual) behaviours and reduced the occurrence of inactive and social behaviours across all colours of enrichment objects. In terms of engagement time, we observed very small differences between the uncoloured and green enrichment objects, while engagement was slightly shorter with the red enrichment object. Based on the results, we can infer that the design of the enrichment object is appropriate for captive tamarins and that the colours of such enrichment objects may not influence their behaviour.
Our study may serve as a starting point for other studies examining the effect of colour on the behaviour of monkeys, such as tamarins and other broad-nosed monkeys. A limitation of our study is the small number of animals studied. In addition, we do not have information on whether homozygous or heterozygous females are present in the studied group, on the basis of which we could confirm trichromatic vision within our group. The study could be improved by pre-acclimating the monkeys to the object and re-exposing them to all enrichment objects to reduce the influence of neophobia among the tamarins. The study could also be improved by longer period recording after object exposure, which would allow us to compare post-feeding behaviours with pre-feeding behaviours. We could also compare multiple colours, which could serve as a starting point for further research to examine the effect of the colour blue, which is also believed to reduce the effects of stressful situations in primates.
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