In Newquay zoo there are two yellow breasted capuchins Tux and Pat both are male and they are both brothers, we wanted to find out if there is a dominance hierarchy between them during feeding times. From early looking it would seem that there is dominance in favor of Tux the large, stumpy tailed capuchin. So we set up a study to see if our thoughts were correct. We did this by using a one zero focal behavioral study, for 5 hours with 15 minute slots over a 1 week period to measure the dominance and submissive behavior between Tux and Pat when they were being fed to measure how dominant Tux.
To get a thorough understanding of the dominance shown by Tux we put together a ethogram to be able to mark what behaviours he was doing the main behaviors shown were: Eating (when Tux was doing nothing but filling his stomach), Submissive Grin (Scientists also call this the ‘silent bared- teeth display’. The lips are apart, and the corners of the mouth are down-turned. Capuchins use this face to say they are not a threat, or as part of courtship.), Bared Teeth (recorded when ever teeth were displayed but directed at something, also barring the teeth was accompanied by raised tail and lower body), Loud Vocal (recorded when a vocalization was louder than a chatter but directed at something) Branch Shake (recorded when branches were shook to show other monkeys how strong they are, and when they are annoyed. They also shake branches to scare away predators.) Movement (recorded when Tux was seen to be moving around his enclosure but not for a reason), Threat Face (Capuchins often use this threat face with flattened ears when they are scared. The monkey may also raise its fur and tail.) urine wash (Capuchin monkeys, especially older males, wash their hands and feet with their own urine. This gives them an individual odour that they leave every- where they walk), grooming (Grooming is a very social activity, and monkeys typically groom their close friends and relatives most. The alpha male usually gets groomed a lot by the females.) (How to ‘Speak’ Capuchin, 2013)
When we had put together the ethogram all we had to do was wait and watch, so over a week we went and watched the Capuchins for 5 hours in 15 minute sections, and recorded what we observed in the table corresponding to our ethogram. After this we took our results and created two tables to show our findings.
In fig 1 it can be seen that Tux’s behavior when being fed his behavior was mainly eating, moving, grooming, displacement and misc, than actually any serious dominance behavior to his brother but on occasions he does he will use the threat face and the loud vocalisations towards him to show his dominance. In fig 2 the pie chart shows the amount of behaviours that Tux showed over the 5 hour study, as we can see most of Tux’s behavior he spent most of his time eating or exploring around the enclosure but not showing much dominance towards Pat.
To conclude it seems that during feeding time it seems that there is not dominance between the two but outside of feeding there is a definite dominance during the rest of the time they are together, Tux is a very dominant, larger and stronger of the two, and clearly he no longer needs to show his dominance over his brother due to the time period of the two being together there is no need for it as a hierarchy has been created.
If I was to do the study again I think it would be better if we had more data and I think it needs more in depth ethogram to be able to make sure you get the right data and its correct.
How to ‘Speak’ Capuchin. 2013. Visual Signals and Behaviours. [online] Available at: http://www.educationscotland.gov.uk/Images/capuchin_behaviour_tcm4-669208.pdf [Accessed: 4 Dec 2013].