We left the pasture behind and squirmed beneath the electrified fence to gain access to the gallery forest. The shaded canopy wending alongside a trickling stream sheltered a riot of vegetal life. How I had missed being in forest! As we followed the trail alongside the fence, we crossed patches of the forest floor that had been smoothed over by the regular passage of foraging cattle.
Not far along, Xyomara’s keen eyes spotted movement in the canopy. We tiptoed ahead and craned our necks upward. Our guide’s eyes brightened in recognition: above us was a tree-full of boisterous squirrel monkeys (Saimiri cassiquiarensis albigena), which happened to be Xyomara’s favorite species. These energetic little primates, of dunnish color with beady, intense eyes were too busy foraging to pay much attention to us. They left no leaf unturned as they searched for insects, which make up the majority of their diet, in the canopy. The monkeys occasionally peered at us with their heads cocked quizzically to the side, nearly upside-down, an adaptation that according to Xyomara helps them scan the undersides of leaves for prey. To sketch them, I had to be quick, given their irrepressible twitchiness! We returned to the farm in high spirits. To have found this group so quickly and so close to camp boded well for the rest of our trip.
In Colombia, the nomenclature of these monkeys can be confusing: they are often referred to locally as titis, not to be confused with the English name for a completely different kind of monkey, the monogamous titis (we will meet them later). Even more confusingly, in some regions titis is the local Spanish name for tiny tamarin monkeys, which are neither English-name-titis nor sapajus! ¡Ay caramba!
The following day Jorge dropped us off in a more distant patch of forest across a stretch of partially-flooded cowfield. Sonia stayed back at la finca nursing a twisted ankle. After just a half hour’s search, we encountered a mixed species group of squirrel monkeys and sapajus (Sapajus apella fatuellus). Xyomara informed that it was common for these species to travel together. I found this to be a fascinating parallel to similar multi-species monkey affiliations which I have seen in Africa.
I am always struck by how eerily similar South American forests are to African ones: many of the same guilds have been filled by independently-evolved plants and animals (tamanduas, the smaller resident anteaters, resemble pangolins, while squirrel monkeys have something of the chirpiness of red-tailed guenons about them). There are even some familiar friends here: the spiky-barked, fluffy-seeded kapok (Ceiba pentandra) tree is somehow shared between the two far-flung continents, and in both regions domesticated mangos and papayas pepper the farm-forest fringes. But, back to our monkey encounter…
Sapajus are bulky monkeys possessing moderately prehensile tails. Another species from this genus in Brazil is famous for using stone tools to crack open nuts and stick tools similar to those of chimpanzees; thus their behavior is of particular interest to me. As far as I know, no tool use has yet been documented in Colombian sapajus, but perhaps this is just due to lack of data?
We relaxed on the trail and watched the lively juvenile sapajus play-grappling in the trees above us, as the adults went about the more serious business of feeding. At one point a large adult passed through the canopy above me; simultaneously a worryingly chunky branch came clattering down inches from my head! Xyomara, who had observed the monkey’s behavior, told me that it had likely been deliberately thrown or knocked down in order to intimidate me. If so, could it represent a form of tool use? This led us to a fascinating flurry of questions, speculation and research ideas. Could there be potential here for a future study?
Following our multi-species encounter, we heard the famous gravelly long-call of red howler monkeys (Alouatta seniculus) from the direction of la finca. This rumbling noise must be near-deafening up close! We would head that way tomorrow.
As we slogged back across the muddy pasture under the intense midday heat, we were mobbed by a fearless pair of black and white caicas (Vallenus chilensis). These dramatically-patterned birds were noisily protecting their unseen nest. Diligent in their parenting, they swooped so low over us that I had to duck my head. I was unable to explain to them that as a vegan, I certainly had no intention of pilfering and consuming their precious brood!
Having escaped these airborne anxious parents, we next spotted a troop of squirrel monkeys traveling along what has been termed by Xyomara and her colleagues as a ‘living fence’. These fences, separating adjoining fields, are surrounded by a dense strip of trees. Xyomara’s research has shown that these vegetation-covered boundary markers are crucial for the dispersal of primates and other fauna between neighboring gallery forests. We watched as each monkey reached the gap in the canopy over the gate, paused, gathered its courage and then flung itself arms-akimbo across the gap, much as I have seen the similar-sized red-tailed guenons do in Africa. Xyomara used the opportunity to count numbers: she came up with a minimum of 11 monkeys…
© Copyright Disclaimer. Sketches were made by Cleve Hicks, pictures reproduced with his permission. Pictures in this post by Sonia Uribe. All pictures used on this web page are protected with copyrights to Xyomara Carretero-Pinzón. If you want to use any of these pictures, please leave a message on the website. Thank you.