A week ago, I was with the green group collecting data and we had a surprising encounter. While half of the group were feeding on grass in an open area, some members were in a tree near by. These individuals started to scream loudly and vocalise. The rest of the group immediately stopped feeding and ran towards the tree. At first, I thought it was an alarm call and the group was looking for a safe place to stay. But the vocalisations did not sound like an alarm call. So following the direction where the monkeys were looking, I could see a bush at the bottom of the tree. Simon, a young adult male, climbed down the tree and started searching for something inside this bush. I carefully approached the bush for a better look. I was wondering what could be there since the entire group was now on the tree, vocalising. Could it be a snake?
After a few min, a small and terrorised dormouse tried to escape by climbing up the tree. Wrong decision as the entire group of monkeys was following it. I took a video of the action, see below. You will see the dormouse running down the tree. If it is too quick for you, watch it a second time. You can hear at the end of the video an alarm call. Note the difference between the vocalisation when they were looking for the dormouse and an actual alarm call used for a predator.
When you have got this opportunistic and rare observation, it is always difficult to emphasise what was the intention of the monkeys. Were they hunting the dormouse? Were they playing? Were they only curious? I would not conclude to any of these hypotheses yet. If I have the opportunity to be the eyewitness of another event like this, I will let you know.