The Big Brained Primates of Laguna Blanca

In terms of intelligence, capuchin monkeys (Sapajus and Cebus spp) pretty much trump every other primate species (apart from humans!) on the continent of South America. The resident monkeys found in Laguna Blanca’s 414ha Atlantic Forest fragment are no exception!! There are thought to be between 12 and 14 individuals living within the reserve. There is one family group who are currently being habituated by the primate team volunteers and myself. Until recently when the monkeys were located within the humid, winding trails of the forest observers were treated to elaborate displays of alarm calls, fear grimacing (when the teeth are exposed like a smile and the eyebrows raised) and branch shaking. Encounters with the monkeys are brief but still breath taking and leave your heart racing with excitement. Last week the PLT Primate Team, right now consisting of Anna (a long term volunteer from Ireland who completed the same Primatology MRes as me) and myself, experienced the most exciting two hours of my 9 months chasing monkeys in Paraguay. The day began at 5 45am with the 30-minute walk to the South Atlantic Forest. Normally we take the motoloco (the bright red, incredibly fun, temperamental trike) it had died the day before so we began with a walk. We entered trail 1 and began to walk extremely slowly, taking extra care not to make too much noise on the carpet of dead, crunchy leaves. Usual procedure when we find the monkeys is to immediately make our presence known, if the monkeys don’t see you it is impossible for them to become habituated to researcher presence. On this day (and I couldn’t tell you why) I decided I wanted to sneak up on them and try and watch them for a while before announcing our presence. We reached the junctions of trails 1 and E – and heard a loud crash to our right. Monkeys. Painfully slowly – when every part of me wanted to run after the sound in case we missed them – we crept towards the crash. We didn’t hear another one. As we arrived at trail G and turned down a loud, hollow knocking sound greeted us. My heart sank thinking the monkeys had gone and all we could hear was a woodpecker. As we stole down trail G we looked up. Monos. The family group was in the tree in front of us. I quite literally stopped breathing as I realized what we were seeing. The hollow knocking sound was the monkeys. They were holding hard fruit in their hands and smashing it off the tree trunk in order to open it. Anna and I nearly fell over each other in desperation to get the camera out of the bag and start filming. This remarkable behavior not only perfectly displays the capuchins remarkable dexterity but also their incredible problem solving ability. For two hours we crawled around the ground trying to find the best view of the group, at one point I sat on a nest of biting ants but refused to move as I had a particularly good spot to film from!!! The next day we went out again the next day, this time with Emma as well. As we walked quietly along trail 3 towards the tree we had seen them feeding in before we heard the knocking. This time not only did we manage to film and photograph the fruit cracking behavior but also begging behavior from the younger monkeys!!! After about 45 minutes we were rumbled. The alarm calling began and the group vanished. We went to the bottom of the tree to collect some of the fruit that had been dropped. As we stood under the tree discussing what we had seen we heard a chirp and a crash behind us. Ka’i. Turning around we were faced with the sub-adult male of the group. Sitting about 3 feet above our head he was calling and displaying, generally making a grand show of himself. This is decoy behavior. I’m ashamed to say I fall for it a lot. As one member of the group comes close and displays loudly to draw observer attention, the others make a stealthy get away. Sometimes I think these monkeys are too smart for their own good!! Until next time, Becca