My wife and I recently traveled to Peru for the second time in two years. The first trip to Peru was a combination of her and some of her students netting for bats and me joining her and separating from her students and going a bird tour to the infamous Manu Rd. Our guide, Saturnino, spoke of the hummingbird diversity of northern Peru during that first trip and recommended to come back one day for it. Well, we did. But we were ill-prepared and unaware of the monkey diversity and sightings that would come with our second trip to Peru. It was surprising and a real highlight to our trip.
My wife is a professional bat biologist and professor at Indiana State University. She teaches mammalogy every other semester there. She has broad interests, of course, in all mammals and animals since we typically book birding trips. She doesn’t mind all the birds and my birding obsession and photography. She’s cool about it and it’s one of the reasons I married her. I think on this particular trip she really enjoyed just about everything with the exception of the food and stinky clothes we had near the end of the trip. But I think it was the monkey sightings, photographs, and video that she enjoyed the most. She’ll probably use some of the photographs and video for her classes that I got during this trip.
Our first monkey sighting was on the way to Abra Patricia and the Owlet Lodge. It was on road 5N and Saturnino had spotted movement and it turned out to be Yellow-tailed woolly monkey. Saturnino’s tone of the sighting got us really excited. “Oh my God, it’s a Yellow-tailed woolly monkey!” He repeated this several times and then started adding superlatives. He had never observed one too, and mentioned that as well. Our driver, Omar, pulled the van over off the highway. It was a busy highway too, there were some serious trucks on it. Here’s a map of roughly where we were. We flew into Tarapoto. The red marker is the Owlet Lodge and our Yellow-tailed woolly monkey sighting was roughly 15-20 minutes east of the lodge on the major road there.
Here’s a photograph of the Yellow-tailed woolly monkey we observed there on 5 July 2017. 
Yellow-tailed woolly monkeys are endemic to the Andes and endangered. Very little is known of them apparently and loss of habitat due to logging and development are among the reasons for their endangered status. They inhabit the cool, humid forests of the Andes between 1,500-2,500 meters and have a relatively small distribution in Peru. Most of their habitat seems to be inaccessible due to the ruggedness of the mountains and impenetrable jungle so I imagine their endangered status has to do with that and the ability of biologists to accurately estimate their population size. However, they are cutting the forest there in Peru to grow coffee and raise cattle. Obviously, we were in the mountains at the time of the sighting but I’m uncertain our exact elevation at the time of our sighting. The monkey’s pelage is quite beautiful. It’s a deep mahogany mixed with black. Its pelage gets darker towards its upper body, making its head seem almost black, and a reddish to coca brown color towards their backside and rump area that gives it that mahogany feeling. It has a powerful and thick prehensile tail, and supposedly the underside of the tail is yellowish. I didn’t get a photo showing the yellow on the tail but I did get a photo of it’s thick and powerful tail.
Here’s the plate from the Primates of Peru (2015). The distribution of this species is restricted in the mountains. Forgive the differences in the Latin scientific names. The pamphlet says one thing but I found a different Latin name for this species that I think is the correct one (Oreonax flavicauda).
We watched in amazement as one adult started to eat moss. These monkeys are apparently herbivores but they will eat fruit, leaves, flowers, insects and other invertebrates. They also consume minerals from the soil which many animals in the Peruvian jungle do to probably balance or neutralize the acids in the fruit and vegetation they consume.
I also got some really cool videos of a momma Yellow-tailed woolly monkey with her baby. The baby was incredibly cute and watched us on the side of the road. I filmed this with my spotting scope and Samsung S7.
The rest of our monkey sightings came on the last leg of our journey, the Manu Birding Lodge and the surrounding areas. Saturnino owns and operates the Manu Birding Lodge. He apparently bought it with his father or it was owned outright by his father. His dad was in his mid sixties but still moved and looked like a young man. The Manu Birding Lodge (red marker below) is located along the Rio Madre de Dios. It’s mostly lowland forest and located in southeastern Peru. We flew into Puerto Maldonado and then drove and got on the river at Boca Colorado, the nearest town. There were a lot of miners in Boca Colorado and along the river.
I posted some photos of the miners that illegally mine the river. They sometimes get chased off by authorities but they simply run into the jungle and evade capture. They use mercury to get the gold from the rock and sand. It’s a dirty process and obviously puts mercury into the water. There were large rock mounds about 15-20 feet in height that we observed along the riverbank. The rocky portions of the river is primarily where they mined. Further upriver near the lodge the sediment was mostly mud and silt so there was no mining there.
We observed a lot animals, mostly birds, along the river. I’m going to get back to the monkey sightings at or near the Manu Birding Lodge. The location of the lodge was interesting. The riverbank rose up a few hundred feet and it was a difficult climb. However, the lodge was safe from any flooding that might occur. Only an epic flood could reach the lodge. I think this also made the lodge’s location great for funneling wildlife, particularly monkeys, through the property. Of course, the trees and habitat provided food and cover for the monkeys, but all of our sightings indicated that the monkeys were moving through. I asked Satu about this phenomenon and he added that he thought the loggers nearby were a factor in the some of the movements he observed there. The monkeys were losing their habitat and homes and moving around.
The first sightings of monkeys on our leg at the Manu Birding Lodge came on 10 July 2017 at Collpa Guacamayo de Blanquillo, the well-known clay lick which was only a 30 minute boat-ride from the lodge. We were walking to the clay-lick and happened on a big group of squirrel monkeys crossing our trail.
Here’s a photo of the trail crossing we encountered. That’s a brown capuchin monkey there in the lead with a Bolivian black-capped squirrel monkey. These two species hang out together.
Here’s a not so good photo of the Bolivian black-capped squirrel monkey.
Here’s the plate from the Primates of Peru (2015) that shows the distribution of this particular squirrel monkey. 
Based on my limited research, the Bolivian black-capped squirrel monkey is insectivorous but will also forage on fruits and seeds. They inhabit primary and secondary forests and will scavenge on the forest floor. When we encountered the squirrel monkeys, they were crossing a recently felled section of forest. They may have been scavenging but I really don’t know. They use squirrel monkeys for biomedical research and these particular monkeys are found in a lot of zoos and the pet trade.
The next day, 12 July 2017, we visited Cocha Blanco, an oxbow lake, that was about 20 to 25 minute boat ride from the Manu Birding Lodge. There were some specialty birds there that Satu wanted us to see. However, he first pointed out the Red howlers hanging out in an enormous Capo tree(?). Satu told us they were always up there. That was their lookout. He also mentioned that this lake was the only place he’s seen a Harpy eagle. That made sense since Harpy eagles forage on howler monkeys. We cruised around the lake and observed Giant Otters. Here’s a photo of one of the group of 5 otters we observed on the lake. They were fishing and swimming all over the lake. We observed one eating a fish even. The markings under their chins are unique and can be used in individual identification.
We moved over to the shaded side of the lake. The sun in South America is incredibly hot and overwhelming. Joy was diagnosed with skin cancer some years and had a simple procedure done to remove the cancerous spot from her forehead. She wanted to stay out of the sun down there. But it was incredible to feel the heat of the sun’s rays upon you down there. You do not want to spend a lot of time baking in the sun there. I mused that if you wanted to interrogate or punish someone, tie them to a chair and put them out in a clearing somewhere. They’ll talk. Well, anyway we approached the other side and Satu noticed some movement in the lower vines and impenetrable vegetation along the lake’s shore. It was a Red howler and it was close. Satu always said things in a manner that indicated the extreme importance or rarity of the situation. A close Red howler meant get out your camera, Mark! I did something better. I filmed the Red howler with my digiscope set-up. Alas, it was two immature male Red howlers wrestling and play fighting.
Later on, after the Red howler octagon match, we left the oxbow lake and returned to the Manu Birding Lodge. We ate lunch and relaxed some but then went on a hike on the property. We observed a saddleback tamarin. Here’s a photo of the Weddell’s saddleback tamarin.
Here’s the plate of Weddell’s saddleback tamarin from the Primates of Peru (2015).
Tamarins are omnivores and can eat a wide variety of food in the jungle. Gestation for tamarins are around 4 to 5 months. They apparently give birth to twins. The young are tended to by the group. Tamarins are polyandrous where a female mates with several males during the breeding season. Tamarins are small-sized monkeys and are preyed upon by jaguars, birds of prey, and snakes. Tamarins can live up to 14 years but I imagine that might be in captivity. In captivity they probably live long lives.
We also observed a Gray’s bald-faced saki monkey on the trails around the lodge later after the saddleback tamarin sighting. It was in the middle of the afternoon now so the sun was blazing and light conditions were terrible. I squeezed off some shots of this species. In retrospect, I think I will shot in RAW format from now on. You can change the exposure and edit your photographs more sufficiently in RAW. Here’s a photograph of the Gray’s bald-faced saki monkey.
Here’s the plate that shows the distribution of Gray’s bald-faced saki monkey.
Save the best for last. That’s exactly what happened to us too. It was the last day at the Manu Birding Lodge, 13 July 2017. The plan was to eat breakfast, pack-up, and leave but take our time doing it. We had plenty of time to get the airport in Puerto Maldonado. It was a late afternoon flight that was actually delayed but we didn’t know it. So we had breakfast, prepared by Satu’s excellent cook. The food at the Manu Birding Lodge was superb. In fact, it was the best food we had I think on the trip. It was agreeable to me and I didn’t experience any digestive problems there. We finished up and packed our bags. After I finished packing, I immediately made a beeline to the garden to attempt to photograph the Festive coquette, a local hummingbird. During my patient wait for the hummer, I noticed some movement in the trees behind us. Of course, Satu joined me to assist in finding the hummer for me. I noticed some movement in the trees and told Satu, “Hey, it’s a monkey.” He immediately identified it as an Emperor tamarin and sprung into action. Joy was on her way to join us and we called out to her. She started her short run and we quickly went down a trail to cut off the tamarins. There was a big group of them and they were moving through the property. Satu knew what he was doing, that was evident the whole trip. He cut them off and even pointed to specific branches that he thought they might use as a bridge to another tree. He told me to set-up on that branch. He was right. The Bearded Emperor tamarins were coming on the path Satu had envisioned. I squeezed off some shots. The jungle was dark and I didn’t have the right settings on my camera. I fiddled around with the settings to try to fix things but the tamarins were moving fast and there was no time. The shot clock was winding down, the bags were packed, and they were loading up the boat to leave. I got off some decent shots, particularly for a free-ranging (wild) tamarin.
Here’s some shots of the Bearded Emperor tamarin.
Here’s the plate for the Bearded Emperor tamarin that shows its distribution in Peru.
Overall, this Peru trip was probably the best trip we ever took. We saw so much. But, to me, it was the monkeys that were the greatest surprise. We observed 7 species on this trip and got some decent photographs and video of them too. I joked on Facebook that the name of the lodge should have an additional word, the Manu Birding and Monkeying Lodge. There was a lot of monkey business going on in around the lodge and surrounding areas. We delighted in seeing them and they always highlighted whatever we were doing or wherever we were going. I think Joy especially enjoyed the nice break from all the birds. The Peruvian jungle was alive with animals, it sustained us every day with the promise of wonderment and serendipity.
Dispatches from a lowly biologist. 