Final-Understanding the Primates of Costa Rica: A Tool for Conservation

This topic submitted by Melinda Marksz ( at 1:49 AM on 5/18/05.

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Understanding the primates of Costa Rica:A Tool for Conservation
I hope to bring a basic understanding of how the primate species of Costa Rica use their habitats to function on a basic, food-seeking level as well as how they function as social animals.Also, I hope to emphasize the importance of maintaining these habitats to ensure that these animals can continue to live in their natural surroundings.

I. Introduction
A.What is a primate?
B.New world monkeys
A. Squirrel monkey
1.Physical appearance
a.Smallest of the Costa Rican primates
2.Diet-feeding and foraging behavior
b.Similar diets to the capuchins-some competition
3.Social organization
a. Very Gregarious-groups of 40 or more
B.Capuchin monkey
1.Physical appearance
a.Distinct white faces
b.Medium size
2.Diet-feeding and foraging behavior
a.Treetop and forest floor foraging
b.Bird eggs,lizards,insects
c.Meticulous eating behaviors
3.Social organization
B.Spider monkey
1.Physical appearance
a.Long limbs, prehensile tails
2.Diet-feeding and foraging behavior
a.Fruits-often use tails to gather food
3.Social organization
a. Group and solitary behavior

C.Howler monkey
1.Physical appearance
a.Largest of the Central American monkeys
b.Prehensile tails
2.Diet-feeding and foraging behavior
a. Selective eating habits
b. Leaves,Fruit
3.Social organization
a. Territorial groups-use vocal communication
D.Squirrel monkey
1.Physical appearance
a.Smallest of the Costa Rican primates
2.Diet-feeding and foraging behavior
b.Similar diets to the capuchins-some competition
3.Social organization
a. Very Gregarious-groups of 40 or more
IV. Conclusion: Primates and rainforest conservation
A. Importance of maintaining our resources


Costa Rican forests hold a vast array of flora and fauna. There are four main species of primates found in Costa Rica, including Capuchin, Spider, Howler and Squirrel monkeys.(1) As the crisis of the rapidly disappearing rain forests of Central America continues, the destruction of these ecosystems is having a very detrimental effect on the habitats of these primates. It is important to understand their social behavior, diet, and habitat so that we can strive to conserve the resources that maintain these species for future generations.

Primates are comprised of any of the various omnivorous mammals distinguished by the use of hands, and complex behavior involving high levels of social interaction and adaptability.(2) The primates of Costa Rica are all included under the classification of New world monkeys (Platyrrhini). New world monkeys are mostly limited to the tropical forest environments of southern Mexico, Central, and South America, thus explaining the prevalence of the four main species found in Costa Rica. Most of the New World monkeys are in the Cebidae and Atelidae families, which are closely related to one another. The Cebidae family includes the capuchin and squirrel monkeys, while the Atelidae includes both the howler and spider monkeys. All of these monkeys are diurnal, engaging in activity both night and day as well as arboreal. These two families are the only primates that have prehensile tails.(3)

Squirrel monkeys

The smallest of the Costa Rican primates, weighing up to 2.2 pounds, is the squirrel monkey, of which two subspecies are found in the country. These are the Red-backed squirrel monkey (Saimiri oerstedii citrinellus) and the Common squirrel monkey (Saimiri oerstedii oerstedii). They both possess the prehensile tail typical of their classification only as juveniles. The Red backed squirrel monkey is distinguished by a gray cap and reddish, saddle-shaped markings on its back with a mostly gray body. However the Common squirrel monkey exhibits a darker cap with reddish body.(4) Although these species are geographically separate, they are net extremely different in their appearances and both exhibit very similar feeding and social group behaviors.

The diet of the squirrel monkey is considered both frugivorous and insectivorous, the latter of which is indicated by their short digestive tract. They also forage for mollusks, and small vertebrates, such as tree frogs.(5)They obtain a majority of water from the foods that they consume, but they will also obtain water from hollows in trees and puddles on the ground.
Squirrel monkeys are extremely social animals, often living in very large groups of 40-70 individuals. Surprisingly, there is no real sexual hierarchy that exists within the group, and the animals are mostly highly egalitarian, showing very little aggression. In fact, females often readily travel between groups without male competition becoming a factor.(6)This species usually chooses to sleep in the canopy of the forest and the groups often sleep in the same tree or trees for a few consecutive nights.(7) Females communicate with chuck calls that indicate spatial and foraging context within the group.(8)

Capuchin monkeys

Capuchin monkeys (Cebus Capucinus ) are the second largest primates found in Costa Rica. Weighing from 3-8 pounds, these primates are distinguished by their black skull cap and white faces with a black back and prehensile tail.(9)The only subspecies that can be found in the country is the White-throated capuchin, and they are dispersed among the low lying forests.

All members of the genus Cebus are omnivorous, with the majority of their diet consisting of fruits, but also including some leaves, flowers and a few insects. On occasion, small vertebrates such as birds and lizards are consumed, as well as eggs, crabs, and oysters. In order to obtain such a variety of sustenance, their foraging habits are arboreal in addition to venturing to the ground. Capuchins are known for their meticulous eating behaviors, and often test for ripeness of fruits by biting, squeezing, or smelling them. Some of the harder fruits are pounded on branches or rocks to soften them or to knock out seeds. Besides obtaining moisture from their diet, they often drink directly from holes in trees or ground springs.(10)

The social structure of Capuchins is different from their smaller cousin, the Squirrel monkey. They live in small groups with more females than males. Males can be aggressive, especially when it comes to defending their territory. As a result of this competition, males may emigrate and remain solitary for a time before joining another group. The species usually spend the majority of their time in one sleeping tree within their habitat range and sleep in groups of 2-4 individuals. They have fourteen different vocalizations, including a loud call used to re-establish contact with the croup if an individual becomes separated, and a purring noise used as a friendly gesture.(11)

Spider monkeys

Spider monkeys (Ateles geoffroyi) are the next largest primates to occupy the Costa Rican rainforest. Ateles geoffroyi ornatus and Ateles geoffroyi panamensis are the two subspecies that can be found in the country, occupying the northern and southern regions respectively. The only real difference between these subspecies is in the variation of coat color. All of the species have dark limbs, but can have blonde to almost black bodies. In addition, spider monkeys possess an incredible prehensile tail with a hairless grip, which has a unique grasping capability that functions as a kind of fifth limb.(12)

The majority of the spider monkey diet is based on fruit consumption, however, carefully selected leaves, as well as flowers are eaten as well. They rarely descend to the ground since they are almost unparalleled in their arboreal agility, however, if they do, they are capable of bipedalism and have been known to walk on their hind legs with their long tail curved upwards and held vertically.(13)

Spider monkeys associate in bands of 15 to 25 animals that inhabit areas of forest that are abundant in a supply of food and sufficient sleeping areas. Within the band, they associate in group units of 2 to 8 individuals.(14)The most closely knit groups are usually found among females with offspring, otherwise the units are primarily loose fusion groups. As far as a hierarchy is concerned, the highest ranking individuals usually can be observed grooming others more than they are groomed themselves. Communication within the bands can most commonly be recognized by a friendly greeting call that is said to resemble the whinny of a horse.(15)

Howler Monkeys

Howler monkeys are the most common of the Costa Rican primates. Weighing up to 10 pounds, they are also the largest. The species that is most commonly found in both the low lying and mountainous forests is the Mantled howler monkey, which is distinguished by its dark coat with lighter colored saddle markings, and face that is black and hairless except for a coarse beard. Much like the Spider monkey, they have prehensile tails that have a hairless grip.(16)
The Howler monkeys diet is foliferous and their main sources of food consist of leaves, fruit, and flowers, which vary seasonally and with the availability of resources. Typically, flowers are most abundant during the dry season, and fruits are more available during the wet season. A diet such as this means that they graze almost exclusively on trees. While foraging for food, they spend nearly equal portions of their feeding time eating leaves as they do fruit.(17)

The group size of Howler monkeys ranges from 10 to 20 members,with a higher female to male ratio of about 1 to 3 adult males and 5 to 10 adult females.(18)The females form the core of the stable social unit, and rarely leave their established group. However, as the ratio of males to females becomes lower than is desirable, older males may use aggressive tactics to drive younger males away, or wander off themselves.(19) Social hierarchys consist of older females engaging in social behaviors such as foraging for food more often than the younger juveniles.(20)Communication amongst Howler monkeys is one of their most distinguishing features. Calls include barks, grunts, and howls. Their characteristic howls occur throughout the day in response to any sort of disturbance, and are loud enough to carry over extremely large distances which aids in establishing their territory.(21)


Primates are characterized by their complex social structures and adaptability. We, as primates, often overlook the good of other species in order to increase our own selfish benefits. Thus, as human economy and population increases the forest is being destroyed .The threat to the existence of these primates is growing with the problem of deforestation and the declining habitats inhabited by the Squirrel, Capuchin, Spider, and Howler monkeys.(22)Their feeding behaviors, and social structures begin to fall apart as their food sources and territories are diminished. Although these species all have faced other threats from humans such as hunting or capturing them and selling them as pets, many protective actions have been taken to minimize these threats. However, deforestation is an issue that is not easily remedied. The more we can learn about the basic needs for these species to thrive, the more we can correct the damage that we have already done, and take the necessary measures to ensure the survival of the primates of Costa Rica for many generations to come.

Works Cited:

(1)Berry, Louise, and Christina Miller. Jungle Rescue:Saving the New
World Tropical Rain Forest. New York: Macmillan Company, 1991.
(2)Infoplease, Information Please, Fact Monster, and the Information Please Almanac Copyright 20002005 Pearson Education, publishing as Fact Monster.
(4)Henderson, Carrol L. Field Guide to the Wildlife of Costa Rica. Austin: University of Texas Press, 2002.
(5)Fleagle, John G. 1988. Primate Adaptation and Evolution. Academic Press.
(7)Kinzey, W.G. 1997. Saimiri. in New World Primates: Ecology, Evolution, and Behavior. ed. Warren G. Kinzey, Aldine de Gruyter, New York.
(8)Boinski, S. and Mitchell, C.L. 1997. Chuck Vocalizations of Wild Female Squirrel Monkeys (Saimiri sciureus) Contain Information on Caller Identity and Foraging Activity. International Journal of Primatology Vol. 18, 975-993.
(9)Costa Rica. 1995. 13 Mar. 2005
(11)Online: Online:
(15)Novak, Ronald. 1991. Walker's Mammals of the World, 5th Ed, Vol I, Johns Hopkins University Press, Baltimore, MD.
(17)Glander, K. 1992. Dispersal Patterns in Costa Rican Mantled Howling Monkeys. International Journal of Primatology, 13(4): 415-436.
(18)Reid, F. 1997. A Field Guide to the Mammals of Central America and Southeast Mexico. New York: Oxford University Press, Inc..
(19)Scott, N., L. Malmgren, K. Glander. 1978. Grouping behaviour and sex ratio in mantled howling monkeys. Pp. 183-185 in D. Chivers, J. Herbert, eds. Recent Advances in Primatology. Volume one. London, New York & San Francisco: Academic Press.
(20)Jones, C. 1996. Temporal Division of Labor in a Primate: Age-dependant Foraging Berhavior. Neotropical Primates, 4(2): 50-53.
(21)Reid, F. 1997. A Field Guide to the Mammals of Central America and Southeast Mexico. New York: Oxford University Press, Inc..
(22)Endangered and Threatened Wildlife and Plants. 1992. U.S. Fish & Wildlife Service.
EC & AC:7/93

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