by Jack Ewing
You would think that after 45 years at Hacienda Barú that I would have seen or heard about everything that the rainforest has to offer. That, of course, is far from being the case. On Tuesday, August 8, 2017 something happened that neither I nor any of our guides or other employees has ever seen or even heard of. I am talking about an act of murder where one wild animal intentionally kills another of its own species. The species was the White-faced Capuchin Monkey (Cebus capucinus), and the act was infanticide. It was witnessed by four Hacienda Barú employees, security guard Guillermo Quesada and three guides, Juan Carlos Bejarano, Deiber Segura, and Rigoberto Pereira. Juan Carlos took some photos with his mobile phone.
The parking and public area near the restaurant at Hacienda Baru borders a secondary forest where sloths, monkeys, agoutis, toucans, and other wildlife are often seen by visitors and employees. The four men mentioned earlier were all in the general area when a terrible ruckus erupted in the trees directly in front of the restaurant. A very large white-faced capuchin male was chattering furiously at a female who had a baby on her back. The rest of the troop was also yelling and threatening the female who took off moving through the trees as fast as she could go. The big male caught up to her, blocked her advance, and attacked her. The female, with the baby still on her back, fought back, and, in the scuffle, they all fell to the ground about four meters below. It wasn’t a free fall because there were small branches which broke the fall and at which they grasped on the way down. At some point during the fall the male snatched the baby monkey away from it’s mother. When they hit the ground he started biting the baby and banging it on the ground. Finally he threw the baby on the ground and went back up the tree. The baby laid still at first but after a few moments began moving the upper part of its body. It appeared to be paralyzed from the waist down. Juan Carlos and Guillermo examined it and determined that the spine was out of line. The rest of the troop was in the lower branches of the trees making aggressive gestures at the female. The big male, on a lower limb a scant two or three meters away, was having what could only be called a fit of rage, screeching, baring his teeth and making threatening gestures at the two men. Juan Carlos had seen many capuchin monkey threat displays in the past, but this was much more extreme. Fearing an attack from the big male he and Guillermo backed away.
The terrified mother ran to her baby and tried to pull it up onto her back, but it was unable to hang on. The witnesses said she wailed and cried almost like a human. The spectacle brought tears to their eyes. She looked into the trees and called to the troop but none would help her. At one point she left the baby’s side, and the large male again descended and brutally grabbed the baby. The female attacked him in a final effort to save her baby, but he batted her aside and, with one savage bite, severed the small monkey’s spinal column. Still furious he grabbed the now dead infant by the legs threw it in the air, dragged it, and finally left it about five meters from the point where he killed it. Then he ascended the tree and rejoined the troop. Juan Carlos took the body into the forest and buried it. The troop wandered away. The mother of the deceased baby stayed near the site for several hours whimpering and obviously in a state of extreme distress. Finally she wandered away.
I have heard of male African lions killing all of the male cubs, sons of a recently dethroned patriarch, but I have never heard of this behavior in primates. It is, however, the only explanation that makes any sense to me. The victim of this act of infanticide was a male, so this may very well be the case. We will never know for sure.