Add patas monkey to the diet...

Last week, we (me and Wash-U Ph.D. student Joshua Marshak) witnessed an interesting hunt. Siberut and Bandit, two older adult male chimps - that were apparently too shy to do so while National Geographic cinematographers were on hand to capture it on film (cinematographers Bryan Harvey and Nathan Williamson JUST left the day before!) - pursued and captured a young patas monkey! At least Siberut managed to... While Josh and I were following these two males who had split off (fissioned) from the larger chimp party, I saw both of them stop and stand staring in the same direction. I couldn't get as good a look at Siberut as I did at Bandit, but Bandit's hair was on end (piloerect). A moment later, both took off at the same time, running quickly to the same spot next the open plateau/short grass grassland where there was a thicket of trees. The behavior seemed to me to be indicative of a monkey hunt - and it was - but I assumed it was vervets they were after. We hung back a little, then came upon Siberut with a monkey in hand. Bandit was still looking up into the trees where we could hear another monkey. We backed off so as not to spoil the hunt in any way but heard the monkey leap from the tree after Bandit began to climb, and did not hear Bandit pursue it. Bandit returned to where Siberut was, and Siberut shared pieces of the monkey with him - the head, an arm and the intestines (only part of which Bandit ate). To my surprise, this monkey was NOT a vervet but an immature patas monkey! It appeared to be a one-year old patas; actually about 14 months given the birth season of patas monkeys here. Having had studied patas monkeys for 2 years (as well as vervets), I was torn as to how to feel. Since I missed the actual capture and killing of the monkey - as well as seeing it basically headless - it wasn't as hard as I thought it would be. Mainly, I was excited to see that these guys COULD capture a patas - the fastest primate - even though it was a young one, only a third of its way to adulthood at the most - and to see that Siberut, the lowest ranking male and one of the oldest, still appears to be one of the best monkey hunters in the Fongoli community. Interestingly, there were no alarm calls given by patas - before or after this hunt. This is similar to the behavior I've seen by vervets towards chimps here too...something I plan to write up for a short publication soon.