Capuchins and Squirrel Monkeys: Primates of Costa Rica (part 2)

 

White-throated Capuchin Monkey

My last blog looked at the largest of Costa Rica's four primate species: the Mantled Howler and Central American Spider Monkey. Now it's the turn of their two smaller relatives.

Capuchin Monkeys are a common sight throughout the Neotropics. Unlike the two species covered in my last blog, which both feed mainly in the forest canopy, Capuchins will forage on the ground as well as in the treetops. Their diet is wide-ranging, both plant-based (fruits, seeds, flowers and buds) and carnivorous (insects, as well as smaller birds and mammals). The name relates to a supposed likeness to brown-robed monks, a likeness that has also (bizarrely) named the cappucino coffee, although I can't see it myself. 

Their sole appearance on our trip was unexpected. All four of Costa Rica's primates prefer to live in forests, ideally primary rainforest. So we weren't expecting to see any in the lowlands of the south-west, where the forests have been largely cleared and farming is the dominant land use.

Wetlands near Cuidad Neilly - not an obvious monkey habitat

We were exploring the extensive wetlands near Cuidad Neilly, near to Costa Rica's border with Panama. Much of the land had been flooded for rice cultivation and the birding was simply sensational. This is a land of waterfowl, waders and herons.

Bare-faced Tiger-Heron near Cuidad Neilly

We found ourselves walking along a track bordering the Rio Corredor, which has been forced into an arrow-straight corridor through the wetlands. The track was flanked by narrow strips of trees and shrubs, and it was there that the Capuchins announced their presence by the sudden wave of activity, chattering and branch-breaking that accompanies a troop of monkeys on the move.

Riverside trees and shrubs - where we discovered the Capuchins

It was difficult to get a good view, as they were mobile and largely concealed by leaves and branches. Every now and again an inquisitive face would pop up in a gap through the vegetation, and it was a challenge to fire off a few photographs before its owner disappeared again.

Capuchin in pensive mood

Like Costa Rica's other primates Capuchin Monkeys have been under the scrutiny of taxonomists, which means that you will find different species names for them in different publications. I favour the IUCN Red List (website) which now calls them the Panamanian White-throated Capuchin Cebus imitator. Why Panamanian and not Costa Rican I do not know: they are found in both countries, as well as parts of Nicaragua and Honduras, but they appear to be more widely spread across Costa Rica than anywhere else. The species has been split from the (similar) Colombian White-throated Capuchin Monkeys found in eastern Panama and parts of Colombia and Ecuador. Sadly, both species are considered at risk, being classed as "vulnerable" by the IUCN due to concerns of forest loss as well as hunting for bushmeat and the pet trade. Their tendency to raid crops doesn't make them hugely popular with farmers, either. 

Capuchin Monkey peering from the forest gloom.

Unfortunately things are even worse for the fourth and final Costa Rican primate, the beautiful Squirrel Monkey - or, to be exact, the Black-crowned Central American Squirrel Monkey Saimiri oerstedii. (Taxonomists don't appear to give much thought to producing snappy or memorable common species names, do they?) This is the rarest of Costa Rica's monkeys, and many visitors never get to see one. However, we were lucky to have brief views of a small group of at least five individuals moving high through the forest canopy in the Piedras Blancas National Park, a marvellous tract of lowland rainforest in the south-west of the country near the town of Golfito. 

Black-crowned Central American Squirrel Monkey - Piedras Blancas National Park, Costa Rica

These are really neat little monkeys, with a distinctive black cap and - unusually for Neotropical primates - a non-prehensile tail. Not that this seemed to impede their movement through the canopy; our five were walking confidently along horizontal vines and creepers before we lost sight of them.

These Squirrel Monkeys occupy a very restricted geographical range (see the map here) being limited to the Pacific coasts of Costa Rica and western Panama. They are well-separated from the Squirrel Monkeys of South America, leading to speculation that they were brought to Central America by man - unlike the other three species described in my two blog posts. However, there are clear differences from the South American species, including a more orange-coloured back (which is not shown well in my photograph which was taken after a short and heavy burst of rain), which suggests that they have been established as a distinct population for enough time to evolve into a separate species.

Animals with limited geographical ranges are often at a greater risk of extinction because they are reliant upon a smaller number of protected areas (among other reasons). That is certainly the case with these Central American Squirrel Monkeys, which are classed as 'endangered' by the IUCN. It doesn't help that they are confined to the lowlands, so cannot benefit from the more extensive range of national parks and reserves along Cosat Rica's central mountain chain. You won't see any up at Monteverde, for example. Continued safeguarding of places like Piedras Blancas and Corcorvado National Parks is essential for their survival. As in my previous blog, I am waving the flag to increase awareness of conservation organisations that working to protect such habitats, such as the World Land Trust. If you are able to lend support then please do.

Sources

Emmons, L. H. (1997) Neotropical Rainforest Mammals: A Field Guide (2nd ed) Chicago: Chicago UP

Henderson, C.L. (2010) Mammals, Amphibians and Reptiles of Costa Rica. Austin: University of Texas Press.

Solano-Rojas, D. 2021. Saimiri oerstedii. The IUCN Red List of Threatened Species 2021: e.T19836A17940807. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T19836A17940807.en. Accessed on 17 February 2025.

Williams-Guillén, K., Rosales-Meda, M., Méndez-Carvajal, P.G., Solano-Rojas, D., Urbani, B. & Lynch Alfaro, J.W. 2021. Cebus imitator (amended version of 2020 assessment). The IUCN Red List of Threatened Species 2021: e.T81265980A191708420. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T81265980A191708420.en. Accessed on 17 February 2025.

Howlers and Spiders: Primates of Costa Rica (part 1)

 

It is just after dawn on a road through the dry forest that flanks the Pacific Ocean. Breakfast has been postponed so that we can catch the morning's first rush of bird activity. A White-throated Magpie Jay flaunts its tasselled crest, while a startling yellow Prothonotary Warbler shimmers through the foliage. Attuned to such small movements, it comes as a surprise when a large black object crashes through the bushes and pauses in a fork of branches to give you a hard stare. This is a Mantled Howler Monkey Alouatta palliata, the most conspicuous of Costa Rica's four primate species. 

Howlers can turn up in forests all over Costa Rica, from the coast to mid-elevation rainforests (around 2,000 metres up). We first heard them at Pocosol Biological Station, a rainforest research facility at the end of a long and bumpy track through the foothills, where their soundtrack of hooting calls echoed over the forest canopy as dawn was breaking. But they didn't show themselves at Pocosol: our first distant sighting was of several black specks in trees across the Rio Frio down on the Nicaraguan border at Los Chiles a couple of days later, where the now-familiar Howler chorus accompanied the evening bustle of comings and goings on the town's busy waterfront.

After that, Howlers seemed to appear in every large forest that we visited. At Tirimbina Rainforest Reserve, in the foothills on the Caribbean side of Costa Rica's central mountain chain, a troop of Howlers passed through the canopy right above us, sending down one individual for a closer look (below). They were interested in us human visitors, without wanting to get too close; this may be a response to what they see as a possible predator, or it might be just exploiting the potential for a food handout. Certainly, Howlers are tolerant of some degree of  human activity and can occupy more disturbed secondary forest habitats: we saw one near to our hotel entrance at Quinta de Sarapiqui for example.

Mantled Howler Monkey - Tirimbina, Costa Rica

Howler Monkeys are found across the tropical forests of Central and South America where their diet comprises mostly young leaves of a variety of rainforst trees. This isn't the most nutritious of foods, but at least there's plenty of it, although the Howlers need to be careful to avoid eating leaves from the more toxic tree species. This leads to an ongoing evolutionary 'arms race' between hungry monkeys and ever-more sophisticated plant defence mechanisms.    

From the six Howler Monkey species listed by Louise Emmons in 1997, we have jumped to 15 species that are now recognised by world conservation body the IUCN. Several of these newly defined species have very limited ranges, but Mantled Howlers can be found across much of tropical Central America and down the Pacific coast to southern Ecuador. Despite this large range, they are a conservation concern (classed as "vulnerable") as numbers have decreased by at least 30% over 30 years. Threats include hunting and habitat loss.

While Mantled Howler Monkeys may be the heaviest of Costa Rica's four primate species, they are not necessarily the biggest. What Central American Spider Monkeys Ateles geoffroyi (below) lack in bulk, they make up for in reach. These lanky, long-limbed canopy dwellers are well-named.

Central American Spider Monkey - Tirimbina, Costa Rica

Tirimbina Rainforest Reserve (website), which should be on the itinerary of every naturalist visiting Costa Rica, provided our only encounter with this elusive species. Unlike the Howlers, they showed no interest in coming close, and we had to be content with glimpses through the thick forest foliage. The photograph above shows the light-coloured facial markings that distinguish them from the mostly-black Howlers, while the poor image below gives a better impression of their spider-like profile. Although most New World monkeys have prehensile tails that can grip round branches, Spider Monkeys seem particularly adept at using it as a fifth limb, making short work of the complex job of navigating through the tangled forest canopy. They moved with an effortless style.

Spider Monkey silhouette - Tirimbina, Costa Rica

Unlike the leaf-eating Howlers, Spider Monkeys seek more nutritious forest foods such as fruits, seeds, flowers and even some small animals. These can be scarce resources, and as a result Spider Monkeys need to range across a large area of forest. This means that their territories are bigger, sometimes over 100 hectares, than those of the more sedentary Howlers which can manage in under 60 hectares. Mind you, Spider Monkeys tend to move around in bigger numbers than Mantled Howlers: groups can number up to 50 individuals, compared with 10-20 Howlers, although the our Spider Monkeys at Tirimbina were far fewer in number.   

Sadly, the conservation picture for Central American Spider Monkeys is even worse than for the Mantled Howlers. The species has a somewhat limited range, being confined solely to Central America, following a taxonomic split that has separated them from a population in Colombia and western Ecuador now called Brown-headed Spider Monkeys Ateles fusciceps. These are also endangered. Central American Spider Monkeys have suffered an even greater population loss than the Howlers: a 50% reduction over 45 years. Habitat destruction is the main culprit, although hunting for bushmeat and the pet trade is also a concern.

While Costa Rica can boast an excellent network of protected forests, this doesn't mnean that the future of species like these two primates is secure. Conservation organisations working to safeguard such habitats, such as the World Land Trust which I have been supporting for over 20 years (and which operates on Costa Rica among many other locations), need all of the help that they can get. 

Right - two primates down, and two to go. Watch this space.

Mantled Howler - Quinta de Sarapiqui, Costa Rica

Sources

Cortes-Ortíz, L., Rosales-Meda, M., Williams-Guillén, K., Solano-Rojas, D., Méndez-Carvajal, P.G., de la Torre, S., Moscoso, P., Rodríguez, V., Palacios, E., Canales-Espinosa, D., Link, A., Guzman-Caro, D. & Cornejo, F.M. 2021. Alouatta palliata (amended version of 2020 assessment). The IUCN Red List of Threatened Species 2021: e.T39960A190425583. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T39960A190425583.en. Accessed on 02 February 2025.

Cortes-Ortíz, L., Solano-Rojas, D., Rosales-Meda, M., Williams-Guillén, K., Méndez-Carvajal, P.G., Marsh, L.K., Canales-Espinosa, D. & Mittermeier, R.A. 2021. Ateles geoffroyi (amended version of 2020 assessment). The IUCN Red List of Threatened Species 2021: e.T2279A191688782. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T2279A191688782.en. Accessed on 02 February 2025.

Emmons, L. H. (1997) Neotropical Rainforest Mammals: A Field Guide (2nd ed) Chicago: Chicago UP

Henderson, C.L. (2010) Mammals, Amphibians and Reptiles of Costa Rica. Austin: University of Texas Press.