South America is a true haven for nonhuman primates and thousands of other animal species as well. Spacious, lush, rich with food and flowing water, the forests of South America holds a large percentage of all the Earth’s plant and animal species, many of which are contained within the Amazon basin. Formed as a drainage base of the mighty Amazon River, the Amazon basin is about as large as the continental United States and is covered by the world’s largest rain forest. And the rain almost never goes away here, with precipitation falling about 200 days out of the year. Yes, 80 inches of rain a year may sound gloomy to most of us, but these massive amounts of moisture help cultivate lush vegetation and plenty of food for millions of animals. In fact, we don’t even know how many unnamed animals exist in the basin since there remain vast unexplored areas, completely devoid of human life. For this reason, South America contains the best preserved sections of wilderness on Earth. In the more populous areas, many countries are extremely proud of their beautiful landscapes and work hard to preserve their lands, but some areas of South America are in danger of becoming sad statistics as deforestation rates have steadily increased over the past 50 years as people cut down the trees to form cattle grazing and farm lands. Groups like The Nature Conservancy are hard at work to find forest-friendly business solutions that benefit the people of South America without compromising their beautiful homeland. These initiatives benefit all primates, including the nearly 100 species of primates in South America that rely on a clean place to call home.

Primate Groups of South America

Prosimians

Tooth combs are so last Eocene in South America.  (In other words, no prosimians live there currently!)

Monkeys

All of the nonhuman primates residing on South America are monkeys and are known to primatologists as Platyrrhines, Neotropical monkeys, or New World monkeys. Whatever the moniker, South American monkeys all share a few things in common, such as wide noses, curved fingernails, an arboreal way of life (stick to the trees), and sets of chompers with 12 total premolars (you know, the teeth next to your canines and before your molars…humans and Old World primates only have 8).

Callitrichids (KAL-I-TRIK-IDS) are the “little fellers” of South America, but are actually quite a successful species despite being er…vertically challenged.  The group includes over 30 species of squirrel-sized marmosets and tamarins. All are primates that lack opposable thumbs but do come equipped with long tails used for balance while hopping across branches. Their “claw-like” nails cling onto the sides of trees while their sharp teeth scrape out tree gum and sap.

What’s the difference between a nail and a claw, you might ask? Claws, fingernails, and toenails are hardened outgrowths of skin cells on the end of mammal digits. When you get your mani/pedi, the stylist is working on the unguis, which is the top portion, and in our case is broad and flat. If you look at your dog’s paws, you will also see the unguis, which is the hard part on top, but it is very strong and rounded downward. Beneath your dog’s unguis is a thick, soft layer called a subunguis, which is an extension of her toe pads. That same layer (subunguis) on primate fingers and toes is not nearly as thick as in other mammals, and primate nails tend to be wide rather than sharp and curved.  So, a “claw-like nail” is a very hard, sharp, curved nail that callitrichids have on all their digits except the big toe.

Tamarins are different from marmosets in that they tend to be a little larger in body size and have differently shaped bottom teeth. Instead of growing upward, marmosets’ hard incisors jut out to the front like little tusks and are used to scrape holes into trees so they can feed on the soft gum and sap underneath.

Callitrichid Love!

(In the style of 2PAC)

Callitrichids…..know how to party

Callitrichids….know how to party

In the citaaays of South A.

In the foreeeests, the forests of the Amazon.

They keep it rockin’. They keep it rockin’.

Throw up your clawed nail if you feel the same way!

Shake, shake it baby.

Shake, shake it mama.

Shake it Calli!

Titi monkeys (Callicebus sp.) are another small-bodied South American primate, about twice the size of most callitrichids but at about two pounds, still much smaller than many of the other Neotropical monkeys. One interesting feature about titi monkeys is their tendency to form monogamous relationships, which is actually a fairly rare occurrence for most primates. Owl monkeys (Aotus sp.) are also monogamous and about the same size as titi monkeys, but with one key difference. Owl monkeys are the only living nocturnal monkeys, meaning that they are going about their regular activities of foraging and moving about while all the other monkeys are away in dreamland.  The night monkey lifestyle is most likely a recent behavioral change since owl monkeys do not have a whole lot of the features we would expect a nocturnal animal to have, with the exception of their large eyes. Shifting to a nighttime schedule is most likely a wise way for the owl monkeys to avoid some of the large birds that tend to hunt bite-sized monkeys during the daylight hours.

You might say beauty is in the eye of the beholder when it comes to the uakari (pronounced WAH-KAH-REE). Cross the red, bald head of a vulture with the round, shaggy body of the abominable snowman, and you start to get a mental picture of a uakari (Cacajao sp). Not a whole lot of field research has been done for three species of uakaris since they live in the Amazon river basin which becomes completely flooded with water for six months out of the year. However, we do know that uakaris are seed eaters with specialized teeth that they use to open nuts and tough fruits to get at the seed inside.

Other South American seed eaters include the sakis (Pithecia sp) and the bearded sakis (Chiropotes sp).  Unlike the uakaris which only have little stump-tails, sakis and bearded sakis have long bushy tails, so fluffy that unfortunately, these monkeys are sometimes hunted just for their tails which are made into furniture dusters. Sakis are about five pounds and are considered to be marvelous leapers as they move through the lower levels of the forest in search of tasty seeds. Bearded sakis are a little larger than sakis and sport…yes, you guessed it…beards. Bearded sakis usually move about in their habitat on all fours, but will stop and hang by their feet while feeding on hard fruits, seeds, and insects.

Now, howla’ if you love howler monkeys! Named for their extremely loud roars, howler monkeys (Allouatta sp) scream and grunt to advertise their position to other monkeys in the forest. Especially loud at dawn and dusk, these loud calls are made possible by their enlarged jaw bone which forms a hollow chamber in the throat and the specialized hyoid bone, which is shaped like a cup and helps resonate the sound even better. Though females are rowdy enough in their own right, males tend to have larger jaw and hyoid bones, and thus produce louder calls. Howler monkeys are relatively large monkeys, weighing from about 10 to over 20 pounds.

Some howler monkey species, such as the black howler (Alouatta caraya) are dichromatic, meaning the males and females are different colors. In the case of the black howlers, males are black and females and youngsters are light, yellowish brown. Howler monkeys have strong prehensile tails that they use to loop around branches for balance while they feed on leaves and fruit.

Grasp! It’s a prehensile tail: and oh, how handy to have an extra arm! While many people assume that all monkeys can hang by their tails, there are in fact only a select few with this capability. The only monkeys with grasping tails are found in the New World and include the howler monkeys, spider monkeys, woolly monkeys, and capuchins (though capuchin tails are not as strong as the others).  Most primate prehensile tails have a tough layer of skin with a pattern of ridges that is unique for each animal, just like a fingerprint. This skin grabs around branches while the monkeys move about, leaving both their hands free to pick tasty food and reach for other tree limbs. Prehensile tails are nature’s very own “hands free” devices!

Spider monkeys (Ateles sp) are another large-bodied Neotropical monkey, averaging over 15 pounds. Males and females tend to be about the same size as each other, and are both characterized by their long arms, legs, and prehensile tails. And while for many animals, a quick glance at the back end would clear up any confusion as to whether the individual in question was male or female, it’s just not that easy in spider monkeys. Males are not what you would call “well-endowed,” and females are equipped with a long clitoris, resembling the typical male anatomy. The reason for this unique anatomy actually lies in the nose. (Say what?) Genetic evidence suggests that spider monkeys (along with many other Platyrrhines) have functional vomeronasal organs. A vomeronasal organ (a.k.a. Jacobson’s organ) is a bundle of cells that are extremely sensitive to pheromones, or tiny bundles of chemicals that send out signals regarding the state of the body, such as one’s overall health or readiness to mate.  Spider monkey females produce pheromones that are carried out of the body in their urine, and the enlarged clitoris is used to help deposit these pheromones in key places for aromatic communication with both male and other female spider monkeys.

Muriqui, or woolly spider monkeys (Brachyteles arachnoides), are similar to spider monkeys but are larger (up to 30 pounds!) and have teeth resembling those of howler monkeys. Found only in sparse rainforest patches in southeastern Brazil, the muriqui is very close to extinction due to habitat loss. Not to be confused with woolly spider monkeys, woolly monkeys (Lagothrix sp) are found in the upper portion of the Amazon and also the cloud forests of Peru. At about 20 pounds in body weight, woolly monkeys sustain their healthy appetites with fruit, insects, and leaves that they find high in the rain forests.

Photo by Luciano Candisani

Found both high and low throughout Central and South America, squirrel monkeys (Samiri sp) are small, (you guessed it) squirrel-sized primates that tend to move around on all fours, leaping from tree to tree when need be. An interesting feature of squirrel monkey society is that most of the time, females are dominant to males, with adult males hanging out on the outskirts of the group, completely subordinate when it comes to accessing the best resources. Until mating season, that is. During this one stimulating time of the year, males begin to bulk up, putting on layers of fat and turning into little Tasmanian devils, aggressively competing with other males for female attention and taking dominance even over the females when it comes to food access. It seems that the bigger the male, the more likely they will be to win fights and also father babies, so the competition at this time is ruthless.

Finally, one of the most recognized primates in the world is the capuchin (Cebus sp). Sometimes called an “organ grinder monkey,” you’ll recognize the capuchin in many a motion picture since they are extremely intelligent and small, making them easier for a handler to manage than larger monkeys and apes. Ross had a pet white-faced capuchin named Marcel in Friends, Dexter the brown capuchin wreaked havoc for Larry Daley in Night at the Museum, and white-faced capuchins performed many crazy antics on George of the Jungle. Despite film maker’s usual portrayal of these monkeys right alongside lions, gorillas, and other African animals, capuchins are only found in Central and South American jungles, sharing their space with jaguars, macaws, and tapirs, to name a few. Capuchins have one of the largest brain to body ratios of all primates and have been shown to participate in some pretty advanced activities, such as using tools to get food, using millipedes as an insecticide, and solving complex puzzles in the lab. (Image of Cebus apella by Arthur Chapman)

I want a monkey! Although many people dream of having a cute little companion about their house to perform amazing tricks and offer them countless hours of enjoyment, a capuchin (or any primate for that matter) is not an optimum pet to own. We at iloveprimates.com do not condone the private ownership of primates as pets based on many principles. Nonhuman primates can catch human diseases and also pass disease to humans. (Did you know that something as simple as a cold sore virus can kill an Old World monkey?) In addition, all nonhuman primates are highly social animals and need variable social contact for the majority of their existence. This form of social contact should come in the form of fellow members of the same species, NOT Homo sapiens. Wild primates have large home ranges and complex interactions with a variety of elements in their environments, and even the best designed zoos must work very hard to provide enough stimulation to prevent mental problems that arise when a highly intelligent animal has its freedoms virtually eliminated. Monkeys and apes are purchased as baby animals but usually become unmanageable when the hormones of adulthood set in. Pet owners are frequently attacked and often resort to cruel restraint methods, such as tooth removal and permanent caging, or even shooting as in a recent case with a chimpanzee in Connecticut. Once pet owners have had enough of the mess and hassle of such a demanding pet, they begin to search frantically for a new home. However, human-raised monkeys and apes have a hard time relating to other members of the same species since they were not properly socialized as youngsters, and most institutions housing groups of primates will not accept them. The best way to enjoy primates is to invest in an annual membership in your local zoo where you can watch primates interacting with each other for as many hours as you’d like! Or, save up for a trip to South America where you can visit primates at their very best…in the wild!

Apes

No apes naturally occur in South America, and to our knowledge, never have been; but for fun, check out our Infamous Primates section for more about the Mapinguari, a rumored ape-sloth-man like creature rumored to exist in the Amazon.

Humans

With a population sitting at about half a billion, humans are widespread throughout South America. The continent now houses various native groups as well as people of European, African, and Asian descent that arrived much later from the original human settlers. People arrived on South America approximately 15,000 years ago, most likely traveling first from Asia to Beringia (a mass of land that once existed between Asia and North America) and later making their way down the west coast of North America and into Central and South America.  See this article from Science Daily for more about their long journey. Some of these immigrants gathered together in permanent settlements, eventually forming highly advanced civilizations, including the Mayas, Aztecs, and Incas. However, upon the arrival of the Europeans from Spain and Portugal in the 1500s, those mighty cultures had been essentially decimated by disease and warfare.

A few groups of indigenous tribes survived, however, and there are now some 300 groups of small tribes that lay claim to their ancestral lands. These groups have unique cultural traditions, and fascinating work has been done by anthropologists to uncover the intricacies of the “primitive state” that is present in all of us but usually disguised by the hustle and bustle of our fast-paced lives. Though much information exists regarding the Yanomamo, Wari, and Moche cultures (to name a few), some South American indigenous people remain completely isolated from all contact with the outside world, their existence documented from afar by South American governments. Most of these uncontacted tribes dwell in the rainforests of Brazil and Peru, whose law-makers and concerned scientists are fighting illegal loggers from destroying the land to keep these humans protected from uninvited intrusion by the outside world.

Primate Fossils

The South American fossil record for nonhuman primates is somewhat skimpy, given what we might expect for a continent that currently holds so many living primates. Primate fossils have been found in Colombia, Brazil, Bolivia, Chile, and Argentina, with the most specimens coming from Miocene deposits in Patagonia (the area waaay down south in South America).  The fossils from this time period suggest that these ancient primates were quite similar to living owl monkeys, howler monkeys, and squirrel monkeys. A few unique primate fossils have been found from relatively recent times (Pleistocene), including Protopithecus brasiliensis, a large primate with a spider monkey-like body and howler monkey-like skull and double the body size of the largest living New World monkeys.

Bones from early the Eocene and early Oligocene primates are non-existent to date in the South American record, thus creating a puzzle capable of challenging even the great Erno Rubik himself. If there were no primates on South America prior to the anthropoids we’ve found from the Miocene, then how did all the little buggars get to S.A. in the first place? South America was once a lone island continent, disconnected by water from its neighbors throughout the time when primates were first popping up in other parts of the world. So, what to do if you’re a primate looking for greener pastures? Over the ocean and through the sea, to South America we go! Although scientists are far from reaching a consensus on the origins of Neotropical monkeys, current evidence suggests that primates migrated to S.A. from Africa during the Cenozoic when a huge drop in sea level occurred, exposing a chain of islands through the Atlantic ocean that could have allowed for rafting events by early anthropoids. (For more about “rafting,” visit our Madagascar page!)