Ateles geoffroyi

Geographic Distribution and Habitat

Ranging from the lush lowland forests at the foot of the Sierra Madre Oriental mountain range on the coast of northeastern Mexico, down through the steaming tropical forests and mangrove swamps of Panama, Geoffroy’s spider monkeys call the ecologically and culturally diverse isthmus of Central America their home. They reside in a range of different types of forests, including evergreen tropical forests, lowland tropical forests, dry successional deciduous forests, cloud forests, and mangrove forests. Their northernmost range includes the Mexican states of Veracruz, Oaxaca, Tabasco, Chiapas, Campeche, Yucatan, and Quintana Roo. Traveling southward, their range continues through Guatemala, Honduras, Nicaragua, Costa Rica, and Panama. Past Panama, there have even been some dubious reports of a subspecies known to science as Ateles geoffroyi grisescens, commonly called hooded spider monkeys, living between the southern border of Panama and the Baudó Mountains of northwest Colombia, but these reports have not yet been confirmed. 


Where do spider monkeys get their name? Can these Peter Parker monkeys thank a radioactive spider bite for their tree-swinging speed and agility? No. Spider monkeys get their name from the way their long legs and tails resemble a spider’s legs. No doubt named by a squirrely naturalist who upon seeing them fled through the jungle in fear of being pursued by Shelob’s brood. But arachnophobes fear not, upon closer inspection the Geoffroy’s spider monkey looks a lot more like us than any spider, all except for one small detail; unlike other primates, spider monkeys are nearly lacking thumbs. In fact, “Atles”, the genus incorporating spider monkeys, is Latin for “imperfect” in reference to their vestigial thumbs. 

Who was Geoffroy and why was he so possessive of this spider monkey? “Geoffroyi”, the species name, refers to the early 19th-century French naturalist Étienne Geoffroy Saint-Hilaire whose theories, though incorrect themselves, paved the way for modern theories of evolution, notably those of his student, Charles Darwin. His influence on the field of natural history is such that a farrago of unrelated species have been named in his honor including tamarins, turtles, cats, bats, and catfish. But enough about Geoffroy, let’s talk about Geoffroy’s spider monkey.     

Geoffroy’s spider monkey is a species of many names. In English, you’ll also find it referred to as the black-handed spider monkey, black-headed spider monkey, or the Central American spider monkey. In Spanish it is known as mico, mono araña or mono colorado. 

Geoffroy’s Spider Monkey belongs to the family of primates known as Atelidae. It contains 26 living species of American monkeys (previously referred to as “New World monkeys”).

Around 2.2 million years ago, a common ancestor of Geoffroy’s spider monkeys and spider monkey species of northwestern South America crossed the Baudó Mountains of northwest Colombia, a range that has acted as a barrier ever since. Over the millenia, Geoffroy’s spider monkeys have diverged into several subspecies on the Central American isthmus. While scientists of the mid-twentieth century described these subspecies in regards to cranial morphology and color of their fur, recent genetic technology and improvements in morphological techniques have now better categorized the Geoffroy’s spider monkey into six subspecies (with a seventh being doubtfully in existence). These include:     

    • Yucatan spider monkey, Ateles geoffroyi yucatanensis
    • Mexican spider monkey, Ateles geoffroyi vellerosus
    • Nicaraguan spider monkey, Ateles geoffroyi geoffroyi
    • Ornate spider monkey, Ateles geoffroyi ornatus
    • Azuero spider monkey, Ateles geoffroyi azuerensis
    • Black-browed spider monkey, Ateles geoffroyi frontatus 
    • Hooded spider monkey, Ateles geoffroyi grisescens

How does the Geoffroy’s spider monkey relate to other monkeys? Further genetic studies have shown that the Geoffroy’s spider monkey’s closest relatives are the white-fronted spider monkey and the brown spider monkey. Spider monkeys branched off from woolly monkeys and muriquis about 3.59 million years ago. Howler monkeys are thought to have branched off from other Atelides over 10 million years ago.

Geoffroy's spider monkey range, IUCN 2023

Size, Weight, and Lifespan

Now that we have got their multiple identities down, let’s take out the measuring tape. As far as American monkeys go, Geoffroy’s spider monkeys are the biggest of the bunch. From head to rear, male Geoffroy’s spider monkeys range from 1.3 to 2 feet (39 to 63 cm), with a weight between 16 and 20 pounds (7.4 to 9 kg). Their tails can tack on an additional 2.3 to 2.8 feet (70 to 86 cm). 

Females tend to be slightly smaller on average. From head to rear, they range from 1 to 1.5 feet (31 to 45 cm) and weigh in at between 13 and 18 pounds (6 to 8 kg). Female tails add on about 2.1 to 2.5 feet (64 to 75 cm).

Scientists have yet to discover the maximum age of Geoffroy’s spider monkeys in the wild, but in captivity, they can live from 33 to 47 years.


Imagine this: You’re in the Guatemalan lowlands sitting atop a Classic Mayan pyramid at Tikal where George Lucas shot an iconic scene of Star Wars: A New Hope. The jungle steams with early morning moisture, and in the air is a cacophony of sounds. You see rustling branches below and suddenly a family of shadowy swinging creatures darts between trees. Are those the Ewoks of the Endorean moon leaping around down there? I doubt it. Let’s go find out. What does a Geoffrey’s spider monkey look like anyway?

Alright, we’re down on the ground. Before us, one of the culprits is timidly creeping down the trunk of a tree, slinking towards a small watering hole, step by anxious step. It’s one of those rare times this species is ever caught on the ground. Her head swivels, her eyes dart about; best to be cautious in case jaguars or pumas wait in shadowy ambush. After all, the Geoffroy’s spider monkey is an arboreal species, meaning they live in the trees. To come to the ground, a place as alien to them as the canopy is to us, takes some chutzpah. In fact, evolution has shaped them for the trees. Take a look at those long arms, a quarter longer than their legs, and perfect for gracefully navigating the upper canopy. Curled behind them is a long prehensile tail. These tails are perfect for suspensory hanging, gripping branches above, and freeing up their limbs to snag food items that are tantalizingly out of arm’s reach. Dangling in thin air, these monkeys grasp fruits and branches with four hook-like fingers and a stubby thumb that Mother Nature is fussily trying to rub out of existence. Would you want a long pesky thumb getting in your way while zipping through the trees at 35 mph? I didn’t think so. That’s faster than Usain Bolt. In addition to their limbs being an acrobat’s envy, Geoffroy’s spider monkeys, like us and other primates, have forward-facing eyes, giving them stereoscopic vision. This allows their brains to register three-dimensional objects, which comes in handy when one needs to stick a tricky landing fifty feet in the air.

Now back to our nervous friend on the ground. Is it a Geoffroy’s spider monkey? How can we tell? Sure looks spidery to me. Long legs, long tail, check. Dinky thumb? Thumbs up. Opposable toes? You betcha. Now what about the fur? Our friend has a beautiful black coat and a yellowy-white underbelly, but the Geoffroy’s spider monkey comes in a range of colors depending on subspecies and population, including buff, reddish, rust, and brown. Infants are born black, but their fur begins to lighten during the first five months of life. Visible beneath a shock of fur on their head is a patch of bare skin that makes this monkey look like she’s wearing goggles. This patch of bare skin continues down to her muzzle.

And, how do we know our friend is a girl? Female Geoffroy’s spider monkeys have a noticeably large clitoris dangling between their legs that resembles the flaccid penis of the male, only the female’s clitoris is larger. This enlarged clitoris allows male Geoffroy spider monkeys to gauge a female’s reproductive receptiveness. Males will touch the female’s clitoris and smell their fingers to detect subtle cues about their reproductive status. This helps males decide which female to mate with.  


What’s on the menu for Geoffroy’s spider monkeys? When the trees are your home, the branches are your kitchen. Unsurprisingly, their diet comes almost exclusively from the trees. Geoffroy’s spider monkeys spend an enormous amount of their time eating (~33.5-44% by some estimates!). Fleshy and ripe fruit make up a whopping 70 to 80 percent of their feeding time. When you spend that kind of time feeding, you become a master of your craft. Geoffroy’s spider monkeys are considered “ripe fruit specialists”, preferring fruits with high concentrations of lipids as well as those that have on average 1-2% alcohol content from fermentation. But don’t expect to see drunken monkeys stumbling from the trees looking for their Uber. This alcohol content isn’t enough to get them drunk, but it does increase their overall caloric consumption. 

Geoffroy’s spider monkeys love fruit so much it’s even changed their eyes! Like other primates, these spider monkeys evolved color-vision to spot fruit among the leaves. This is thanks to the “spectral” positioning of certain pigments within their eyes that make them better able to forage fruits under poor lighting conditions. 

But fruit alone won’t provide Geoffroy’s spider monkeys with a balanced diet. Protein is important to sustain all that swinging and running through branches. Leaves, particularly those from epiphytic species such as bromeliads, offer one source of protein. Sites can attract large subgroups where these monkeys can be seen tearing off the basal leaves, biting and sucking on them. Leaves are also used as a fallback source of food in times of fruit scarcity. Other types of food sources include flowers, aerial roots, seeds, buds, eggs, honey, bark, insects, palm hearts, and the liquid endosperm or “milk” from inside immature palm fruits. Yum!

What do spider monkeys use to slake down all these tree morsels? Geoffroy’s spider monkeys obtain water from the fruits, leaves, and flowers they eat, but they also drink water directly from tree hollows, epiphytic tank bromeliads, and some land-based sources, such as small streams, particularly around mineral licks.

Behavior and Lifestyle

How does a Geoffroy’s spider monkey spend its day? Like humans, Geoffroy’s spider monkeys sleep at night and use the daytime for their activities. Depending on the season, these monkeys can spend anywhere from one-third to one-half (~33.5-44%) of their day eating and another third traveling in search of food (~32.6-34%). 

How do Geoffroy’s spider monkeys travel? Getting between trees can be tricky, but these monkeys have a number of tricks up their sleeves. Their primary means of locomotion are climbing, walking and running, or swinging from branches using their long arms. This last technique is called “brachiation”. When the going gets tough though, they resort to more creative modes of locomotion. One of the challenges of tree-dwelling is “minding the gap”. Oftentimes, two trees don’t come seamlessly together, instead leaving a space between them. Geoffroy’s spider monkeys will usually make airborne leaps when necessary. In some populations, such as those in Panama, these leaps are more frequent. In some cases, Geoffroy’s spider monkeys employ a unique method called “bridging” in which they pull a neighboring branch towards them and hop on. This is especially useful for mothers with juveniles in tow who may have a hard time making the leap between branches.

When Geoffroy’s spider monkeys are not eating or traveling, they spend about 10 percent of their time on a range of other activities (~9.8-10%). All that eating and traveling can be exhausting. Geoffroy’s spider monkeys can spend anywhere from a fifth to a quarter of their time resting (~12-24.1%), often gorging themselves on fruit, then kicking back to rest in the same tree where they found it.

Fun Facts

Move over gorilla family when it comes to intelligence this spindly primate ranks third in wits, taking an unexpected bronze medal behind heavy-weight fan favorites like the orangutan and chimpanzee. Sure, if it came to shot put or hammer throws the gorillas would best us all, but brain games are where this little egghead thrives. How do we know these monkeys are so smart? For one, Geoffroy’s spider monkeys know who the monkey in the mirror is. Present most monkeys with their mirror image and they bristle at the gall of this intrusive outsider. But not Geoffroy’s spider monkeys. They fall into the lauded category of self-awareness along with the likes of chimpanzees, bonobos, orangutans, and gorillas. Geoffroy’s spider monkeys also excel at memory tasks, remembering the location of fruiting trees in the wild after many months of their first encounter. 

When it comes to living in the jungle, it can get buggy even by a spider monkey’s standards. To get rid of pesky insects this clever spider monkey will rub a mixture of saliva and ground lime tree leaves (a natural insect repellent) on its fur.

Geoffroy’s spider monkeys will sometimes mutually groom with white-headed capuchin monkeys.

The ancient Mayan civilization had a complex cultural relationship with spider monkeys. Geoffroy’s spider monkeys can be seen depicted in pre-Columbian sculptures and pottery. The semi-deciduous Calakmul forest in Mexico contains the largest remaining population of spider monkeys thanks in part to the high densities of large fruiting trees. Due to their proximity to Mayan ruins, scientists have long thought these trees were the result of ancient Mayan agro-forestry. However, an alternative explanation has been proposed. The Mayan ruins offer a home to bats who are known to disperse seeds, particularly those of the bread nut tree, a favorite of Geoffroy’s spider monkeys. The trees take advantage of the high levels of limestone in soil from the erosion of the ruins. This is an important reminder that the ecosystem upon which Geoffroy’s spider monkeys depend is incredibly complex and still not fully understood.

Daily Life and Group Dynamics

As one might expect of these fruit fanatics, fruit availability is one factor that shapes the dynamic relationships within Geoffroy spider monkey society. Essentially, it determines who hangs out with whom, and when. Throughout the year, and even the day, Geoffroy’s spider monkey groups fluctuate in size, a dynamic social relationship that is termed “fission-fusion”. Geoffroy’s Spider Monkeys typically live in large groups of between 16 and 56 members where male members are related to one another and females are from an external group. On occasion, group numbers can reach as high as 100 individuals. On average, there are typically 4 males (4.4) for every 1 female (0.8) in the group and the number of females increases when there is a proliferation of fruit, such as around the wet season. 

At the start of the day, the large group splits into “culinary search committees”, consisting of two to six members. This “fission” of the larger group improves foraging efficiency. Who follows who is based on each individual’s knowledge of food in the area. The high intelligence of Geoffroy’s spider monkeys allows them to memorize the locations of regular food sources. Once a good fruiting source is found, the “search committee” reports back to the group about the feeding sites. By sharing information the whole group obtains a more complete picture of the always changing foraging environment than any one individual could obtain on their own. The fission-fusion relationship is an evolutionary adaptation that allows Geoffroy’s spider monkeys to respond to environments with fluctuating food availability. When fruit availability is high and concentrated in clustered patches, group sizes increase and the amount of area covered in search of food decreases. Groups are larger and change members more often during the rainy season compared to the dry season. Groups of just females are less tightly knit but keep the same members for longer than groups of just males.

Between March and June, the Brosimum–or breadnut tree–an irresistible favorite of Geoffroy’s spider monkeys, grows heavy with fleshy orange fruits, foreshadowing the arrival of the rainy season in May that brings with it an abundance of food. In mature forests, where the density of fruit is ten times greater than in less developed stages of forest, this rich bounty of Brosimum fruits becomes a gathering ground. Large subgroups of Geoffrey’s spider monkeys congregate around these dense patches. Numerous fruits mean that these monkeys don’t have to travel as far to find food. Typically, they forage over large tracts of land. A group of Geoffroy’s spider monkeys can cover up to 6,600 feet (2,000 meters) in a single day, and their home range often exceeds 2,200 acres (900 hectares), but the rainy season marks a time of abundance and less travel. 

However, fruit is not always as readily available throughout the year. The unpredictable and dispersed nature of fruit prevents any one individual or group from monopolizing resources. This has produced a surprisingly egalitarian social structure that lacks any clearly defined dominance hierarchy. Instead of contests for food between individuals and groups, subgroups often scramble to find food, reporting back to the larger group about their findings. Association patterns (time spent together, preferred companions, and group composition) vary between seasons, respond to changes in fruit availability, and are influenced by the sex of individuals. On the other hand, proximity patterns (the physical closeness or nearness of individuals within a social group without social interaction) are minimally affected by changes in fruit availability, suggesting that social factors are more important than food availability in determining cohesion within subgroups.

While there is no one grand poobah of the group and the dominance hierarchy is not as obvious as it is in some other primate species, there are still power dynamics at play. Age-related social status does appear to be important among males, producing several dominant males within a group that appear to mate more frequently than low-ranking males. Despite this, each reproductively mature male mates at least once a year. 

Adult females tend to be more submissive and more nonsocial. When female Geoffroy’s spider monkeys reach reproductive age (around four years old), they break off from their maternal group, sometimes traveling alone or in a coed group. The lack of a cohesive hierarchy in some ways makes strong and permanent bonds less likely to form, particularly among the typically unrelated females. As a result, individuals decide when to leave or join a certain subgroup. Males typically will remain in their kin group. 

Males tend to be both territorial and aggressive, but they direct most of their aggression towards females. Females try to avoid males as much as possible. When they do come together, particularly during the fruiting season, females show a great deal of vigilance. Initially, it was thought that this social vigilance was a way to monitor food sources, but further research has shown that females are wary of aggression from males. While roughly 20 percent of this aggression is physical, the majority (~80%) can be thought of as sexually charged.

This sexually charged aggression occurs most frequently when the female is cycling and is associated with the male smelling the location where the female was previously sitting. The male then ritualistically chases the female through the branches. This is then proceeded by the female courting the male attacker after the chase has ceased. While chases do not culminate immediately in copulation, they do sometimes culminate in the female leaving the subgroup to travel alone with the male aggressor. 

While male-female aggression is more frequent, male-male and female-female aggression does occur on occasion. For females, aggression typically occurs during feeding when in competition for food. Male-on-male aggression does increase in the presence of females, but the amount of diplomacy does. During tense situations, males embrace to clear the air. In the presence of females, the amount of embraces increases as a way to mitigate access to females. “Genital manipulation” is another means for regulating social relationships that can serve to alleviate tension, prompt reconciliation or signal the forming of an alliance. But when it comes to throwing punches, so to speak, Geoffroy’s spider monkeys will grapple with each other. This can include genital manipulation and, in very rare cases, anal penetration. 

However, these cases are rare and males tend to be much more chummy with one another, choosing to galavant around the forest with the boys. Females on the other hand tend to travel alone or with offspring and are more dispersed. Females, in fact, show no interest in being around other females. These intrasex relationships likely hark back to their style of fission-fusion social structure; the females disperse, meaning the males in a subgroup tend to be related to one another.  

Unlike many other primates, social grooming isn’t particularly important to Geoffroy’s spider monkeys. A measly 2.5 percent of their day is dedicated to the task with an average session lasting just two minutes. Instead, their social relationships are shaped by a number of other behaviors, including embraces, kisses, and pectoral sniffs. That said, they still average two grooming sessions a day which occur around noon and late afternoon (4:00-5:00 PM). Nevertheless, grooming still reflects important aspects of their social structure, including intraclass grouping preferences (males like to groom other males), female dispersal and male philopatry, and a long period of juvenile dependence. Females tend to be the ones who groom the most with juveniles being the most frequent recipients of grooming. Males tend to groom other males in this male-bonded fission-fusion society. Both grooming and embraces are valuable social tender between males of the same age. However, as the disparity of age increases so does the reciprocity of grooming. Younger males tend to value relationships with older males more than the reverse, and they give more embraces than they get.


So you want to learn how to speak Geoffroy’s spider monkey. When it comes to communication, Geoffroy’s spider monkeys use both vocalizations and visual displays to get their messages across. Barks, whinnies and squeals, squeaks and screams all have their specific meanings and interpretations. To boot, each individual has a unique vocal fingerprint identifying them like a nametag. Functioning primarily as alarm calls, barks are employed to signal potential threats, while whinnies and screams serve as distress calls, particularly when individuals are separated from one another. Whinnies, however, come with more nuanced meaning: alerting the group to food sources, maintaining contact during foraging, and signaling at dawn and dusk. Interestingly, whinnies from monkeys outside a subgroup exhibit lower fundamental frequencies, increasing their likelihood of eliciting a response whinny over longer distances.

But vocalizations aren’t the only way to communicate. Geoffroy’s spider monkeys also use various postures to send a message. In Geoffroy’s spider monkey “sign language” a curled tail or arched back is used as a threat display to tell other spider monkeys “You’re messing with the wrong guy, pal.” A head shake can be a bit trickier to interpret, either inviting one to play or threatening them with injury. Talk about mixed signals! The fuzzy line between aggression and play is common throughout the animal kingdom and appears even in humans. Best not to get that one wrong. Say you see some impending danger: a puma perhaps or a herd of gawking tourists. Branch shaking and arm swaying are used as visual cues to warn the group of these potentially lethal threats. Together, vocal and visual communications reflect the complexity of this monkey’s social interactions. Okay, you’ve survived your first Geoffroy’s spider monkey Hooked-on-Phonics course. Let’s see how we can put it to use.

Reproduction and Family

What better way to use Geoffroy’s spider monkey language than to communicate your affection (or sexually-charged aggression) for another? As you learned earlier, you know love is in the air when a male smells the spot where a female was sitting, and then chases her madly through the trees. The Geoffroy’s spider monkey has no specific breeding season, meaning all year round is open for potential love-making, so long as each party is of reproductive age. Females become sexually mature at about four while males take about a year longer. So long as they live long and prosper, each monkey will entertain multiple partners in their lifetime. While males do the chasing, females are actually the selective ones, choosing their mates and creating short-lived pairings, known as “courtships”. These flings can sometimes last an entire season. Prior to mating, the male and female abscond from the group, metaphorically closing the curtains for privacy, leaving only them and the female’s juvenile offspring if one is present. Detailing the variety of sexual positions would make for a short Kamasutra. Geoffroy’s spider monkeys mate in a single sitting position, both facing the same direction, with the male seated behind the female and his arms wrapped around her chest and legs wrapped around her waist. This embrace lasts between 8 and 22 minutes.

Females bear young every two to four years. The gestational period is about 7.5 months and will most often culminate with the birth of a single baby, although twins will occur on occasion. These babies are dark in color until about five months of age when they take on the adult’s coat coloration. Unsurprisingly, newborns spend almost all their time in proximity and in contact with their mothers. Due to their intelligence and social complexity, Geoffroy’s spider monkeys have an extended period of dependence on mom, nursing until one year of age. They cling to their mothers’ chests for the first month and a half to two months, after which they can ride on mom’s backs. 

But the time infants spend within one-arm’s reach from the mother decreases with age, and the infant becomes more and more responsible for maintaining that proximity. In the first three years of their life, they reach two milestones. The first milestone is met in the first eight to ten months of life when exploration and independent movement begins. The infant begins to explore relationships with other group members other than its mother. Between about ten months and nineteen months, the juvenile begins to eat solid food. They still need mom’s help to bridge gaps in the canopy. Between nineteen and twenty-one months of age the infant reaches his or her second milestone. The mother begins to reject the infant, preparing it for complete independence. There are no more rides on mom’s back and the infant now must bridge the canopy gaps on their own.

Ecological Role

Geoffroy’s spider monkeys don’t just take fruit and run without giving something back to the trees in return. In exchange for all the delicious fruits, Geoffroy’s spider monkeys assist trees by dispersing their seeds far and wide. Trees benefit from this deal by increasing their seed dispersal range, getting further with Geoffroy’s spider monkeys than they do with either gravity or wind alone. In this way, Geoffroy’s spider monkeys are like gardeners of the forest. In addition to seed dispersal, they fertilize the ground with their nitrogen and phosphorus-rich feces, and also the droppings of organic matter, such as leaves and branches. 

It’s not just the trees that they unintentionally benefit. Watch a Geoffroy’s spider monkey chomp down on some fruit and you’ll notice they’re very messy eaters. Other animals have observed this and conveniently time their visit to coincide with the Geoffroy’s spider monkeys’ meals. While there currently isn’t any direct evidence to show animals like coatis follow Geoffroy’s spider monkeys’ call to the source of the fruit droppings, scientists have speculated this could be the case. Fruit dropped by these spider monkeys makes up a decent portion of the coatis’ diet. As unwitting stewards of these forests, the loss of Geoffroy’s spider monkeys would have a domino effect on the ecosystem.

Conservation Status and Threats

Sadly, Geoffroy’s spider monkeys may not be around for much longer unless serious action is taken to protect them. Human activity has hemmed them into increasingly small islands of forest surrounded by oceans of man-made landscapes. In the past forty-five years, in just three generations, their populations have decreased by at least fifty percent. Geoffroy’s spider monkeys need large tracts of land to survive, but they face intense deforestation and forest fragmentation throughout their range. More than 70 percent of the forest cover throughout Mesoamerica has been lost due to human activity, including clear-cutting for cattle pastures, croplands, expanding tourist industries, and other human-modified landscapes such as roads and buildings. Regenerating forests make up the largest amount of man-made disturbance in the Geoffroy’s spider monkey range. This is forest that is regrowing after logging or slash-and-burn agriculture. If deforestation continues at the same rate, a third (34%) of the remaining habitat for Geoffroy’s spider monkey will disappear by 2063.  

Geoffroy’s spider monkeys’ reliance on fruit makes them unable to adjust their diets as food supplies diminish. They will use these regenerating forests as corridors to travel between forests, but these are becoming few and far between. Habitat fragmentation makes it increasingly difficult for them to reach other areas of forest with fruit. Geoffroy’s spider monkeys have become locally extinct in most areas accessible to humans. Their loud chatter in groups makes them an easy target for hunters seeking meat or pets for the illegal pet trade. These pressures combined with their highly frugivorous diets, low reproduction rates (due to long interbirth intervals and gestation periods), and large home ranges make it difficult for their populations to recover in the short and long term. As a result, the Geoffroy’s spider monkey appears in the IUCN’s “Primates in Peril” listing of “The World’s 25 Most Endangered Primate Species publications” for 2016-2018, 2018-2020, and 2022-2023.  The International Union for Conservation of Nature lists the Geoffroy’s spider monkey as Endangered (IUCN 2020), appearing on its Red List of Threatened Species.

Conservation Efforts

Geoffroy’s spider monkey populations are at risk of extinction across nearly all their home ranges. In locations such as El Salvador, Geoffroy’s spider monkey populations have been restricted to isolated patches of semi-deciduous forests. Sightings are few and far between. Some organizations, such as Paso Pacifico, are attempting to revive these populations in El Salvador. 

According to the International Union for the Conservation of Nature, there exist 400 officially recognized protected areas within the distribution range for Geoffroy’s Spider Monkey. At first glance, this may seem like a lot, but most of these areas are small islands in the midst of largely deforested regions that don’t take into account the natural range of these spider monkey populations and prevent natural wildlife corridors from forming. In addition, many of these regions are “protected” only in name. Staff is often too small to properly prevent illegal logging, trapping, and hunting. In recent years attempts have been made to limit the international trade in Geoffroy’s spider monkeys. An international agreement between governments at the Convention on International Trade in Endangered Species (CITES) aims to prevent the sale of wild animals and plants that are threatened by extinction, but with little funding, enforcement can be difficult in remote areas, particularly in regions of extreme poverty and political upheaval. 

Indigenous territories remain some of the most protected havens for Geoffroy’s Spider Monkey. These include the Mayan Forest between Mexico, Guatemala, and Belize; La Mosquitia between Honduras and Nicaragua; the Indio Maiz-Tortuguero in Nicaragua; Tortuguero National Park in Costa Rica; and La Amistad International Park along the Talamanca mountain range of Costa Rica and Panama. As we humans continue to deforest the world towards an abyss, researchers are scrambling to put together species breeding programs to assure the survival of this beautiful and unique creature. The Species Survival Plan® is one such cooperative breeding program between zoos that aims to preserve Geoffroy’s spider monkey among many other species that are quickly slipping away.

  • Aguilar-Melo AR,  Calmé S,  Pinacho-Guendulain B,  Smith-Aguilar SE, and  Ramos-Fernández G. Ecological and social determinants of association and proximity patterns in the fission–fusion society of spider monkeys (Ateles geoffroyi). Am J Primatol.  2020; 82:e23077. 
  • Arbaiza-Bayona, A. L., Schaffner, C. M., Gutiérrez, G., & Aureli, F. (2022). Mother–infant relationships and infant independence in wild Geoffroy’s spider monkeys (Ateles geoffroyi). Journal of Comparative Psychology, 136(4), 221–235. 
  • Aureli, F., Schaffner, C.M., Boesch, C., Bearder, S.K., Call, J., Chapman, C., et al., 2008. Fission-fusion dynamics: New research frameworks. Current Anthropology 49: 627-654.
  • Bernardi-Gómez, C.,  Valdivieso-Cortadella, S.,  Llorente, M.,  Aureli, F., &  Amici, F. (2023). Vigilance has mainly a social function in a wild group of spider monkeys (Ateles geoffroyi). American Journal of Primatology,  85, e23559. 
  • Busia, L., Denice, A.R., Aureli, F. et al. Homosexual Behavior Between Male Spider Monkeys (Ateles geoffroyi). Arch Sex Behav 47, 857–861 (2018). 
  • Busia, L., Schaffner, C.M., Rothman, J.M. et al. Do Fruit Nutrients Affect Subgrouping Patterns in Wild Spider Monkeys (Ateles geoffroyi)?. Int J Primatol 37, 738–751 (2016). 
  • Byrne, R.; Whiten, A. (1988). Machiavellian intelligence: social expertise and the evolution of intellect in monkeys, apes, and humans. Oxford University Press. pp. 289–294. ISBN 978-0-19-852175- 
  • Campbell, C. J., Aureli, F., Chapman, C. A., Ramos-Fer- nández, G., Matthews, K., Russo, S. E., Suarez, S. & Vick, L. 2005. Terrestrial Behavior of Ateles spp. International Journal of Primatology 26 (5): 1039- 1051.
  • Campbell, C. J. (Ed.). (2008). Spider Monkeys: Behavior, Ecology and Evolution of the Genus Ateles. Cambridge University Press
  • Chaves, O.M., Stoner, K.E. Arroyo-Rodriguez, V. 2012. Differences in diet between spider monkey groups living in forest fragments and continuous forest in Mexico. Biotropica 44: 105–113
  • Collins, A. (2008). “The taxonomic status of spider monkeys in the twenty-first century”. In Campbell, C. (ed.). Spider Monkeys. Cambridge University Press. pp. 50–72. ISBN 978-0-521-86750-4.
  • Cortes-Ortíz, L., Canales Espinosa, D., Marsh, L.K., Mittermeier, R.A., Méndez-Carvajal, P., Rosales-Meda, M., Solano, D. & Williams-Guillén, K. 2020. Ateles geoffroyi. The IUCN Red List of Threatened Species 2020: e.T2279A17929000. 2.RLTS.T2279A17929000.en 
  • Dell’Anna, F., Aureli, F., Damm, J. et al. Grooming reciprocity in Geoffroy’s spider monkeys, and the influence of the opportunity of interaction. Behav Ecol Sociobiol 78, 29 (2024). 
  • Estrada A, Garber P, Pavelka M, Luecke L. 2006. Overview of the Mesoamerican primate fauna, primate studies, and conservation concerns. In: A. Estrada, P. Garber, M. Pavelka and L. Luecke (eds), New perspectives in the study of mesoamerican primates: distribution, ecology, behavior, and conservation, pp. 1-22. Springer, New York.
  • “Geoffroy’s Spider Monkey – Facts, Diet, Habitat & Pictures on”. (n.d.). Animalia. Retrieved March 1, 2024, from:
  • Gomez-Escamilla, N., Téllez-Baños, B., Espejo-Serna, A., & López-Ferrari, A. R. (2017). The use of epiphytic Bromeliads by Ateles geoffroyi Kuhl (Primates, Mammalia) in Chiapas, Mexico. Journal of the Bromeliad Society, 66(1).
  • Havmøller, L. W.,  Loftus, J. C.,  Havmøller, R. W.,  Alavi, S. E.,  Caillaud, D.,  Grote, M. N.,  Hirsch, B. T.,  Tórrez-Herrera, L. L.,  Kays, R., &  Crofoot, M. C. (2021).  Arboreal monkeys facilitate foraging of terrestrial frugivores. Biotropica,  53,  1685–1697.
  • Hartwell, K.S., Notman, H. & Pavelka, M.S.M. Seasonal and sex differences in the fission–fusion dynamics of spider monkeys (Ateles geoffroyi yucatanensis) in Belize. Primates 59, 531–539 (2018).
  • Julián Parada-López, Kim Valenta, Colin A. Chapman, Rafael Reyna-Hurtado; Spider Monkey (Ateles geoffroyi) Travel to Resting Trees in a Seasonal Forest of the Yucatan Peninsula, Mexico. Folia Primatol 15 March 2017; 87 (6): 375–380. 
  • Kumpan, T., & Runzel, K. (2023). The Ontogeny of Prehensile Tail Use in Ateles geoffroyi. University of Northern British Columbia; Sonoma State University  
  • Mohamed bin Zayed Species Conservation Fund. (n.d.). Black-handed Spider Monkey Conservation Case Study. Retrieved February 26, 2024, from
  • National Geographic. (n.d.). Spider monkeys, facts and photos. National Geographic. Retrieved from: 
  • Ordóñez-Gómez JD, Santillan-Doherty AM, Hammerschmidt K (2019) Acoustic variation of spider monkey (Ateles geoffroyi) contact calls is related to caller isolation and affects listeners’ responses. PLOS ONE 14(4): e0213914. 
  • Peters, C.M., Pardo-Tejeda, E. Brosimum alicastrum (Moraceae): uses and potential in Mexico. Econ Bot 36, 166–175 (1982). 
  • Pinacho-Guendulain, B., Ramos-Fernández, G. Influence of Fruit Availability on the Fission–Fusion Dynamics of Spider Monkeys (Ateles geoffroyi). Int J Primatol 38, 466–484 (2017). 
  • Ramos-Fernández, G. and Ayala-Orozco, B., 2003. Population size and habitat use of spider monkeys at Punta Laguna, Mexico. In Primates in Fragments (pp. 191-209). Springer US
  • Ramos-Fernández, G. Palacios-Romo, T., Aguilar, S.; July 18–22, 2021. “Exploring collective intelligence in animal fission-fusion dynamics.” Proceedings of the ALIFE 2021: The 2021 Conference on Artificial Life. ALIFE 2021: The 2021 Conference on Artificial Life. Online. (pp. 82). ASME. .
  • Ramos, E. J. P. (2022). How do spider monkeys (Ateles geoffroyi) modify their environment? Are they the gardeners of Mexican forests? Final Report – Primate Society of Great Britain and Born Free Foundation Conservation Grant. Universidad Veracruzana Instituto de Neuroetología.
  • Regan BC, Julliot C, Simmen B, Viénot F, Charles-Dominique P, Mollon JD. Fruits, foliage and the evolution of primate colour vision. Philos Trans R Soc Lond B Biol Sci. 2001 Mar 29;356(1407):229-83. doi: 10.1098/rstb.2000.0773. PMID: 11316480; PMCID: PMC1088428.
  • Sanders, R. (2022, March 30). Monkeys often eat fruit containing alcohol, shedding light on our taste for booze. Berkeley News.
  • Schaffner, C. M., Slater, K. Y., & Aureli, F.(2012)Age related variation in male–male relationships in wild spider monkeys (Ateles geoffroyi yucatanensis). Primates, 53, 49–56.
  • Slater, K.Y., Schaffner, C.M. & Aureli, F. 2007. Embraces for infant handling in spider monkey: evidence for a biological market? Animal Behaviour 74: 455–461.
  • Slater, K.Y., Schaffner, C.M. & Aureli, F. 2008. Female-directed male aggression in wild Ateles geoffroyi yucatanensis. International Journal of Primatology 29: 1657-1669
  • Slater, K.Y., Schaffner, C.M. and Aureli, F. (2009), Sex differences in the social behavior of wild spider monkeys (Ateles geoffroyi yucatanensis). Am. J. Primatol., 71: 21-29.
  • Smith-Aguilar SE, Ramos-Fernández G, Getz WM (2016) Seasonal Changes in Socio-Spatial Structure in a Group of Free-Living Spider Monkeys (Ateles geoffroyi). PLOS ONE 11(6): e0157228. 
  • Wainwright, M. (2002). The Natural History of Costa Rican Mammals. Zona Tropical. pp. 146–149. ISBN 0-9705678-1-2. 
  • Youlatos, D. (2008). “Locomotion and positional behavior”. In Campbell, C. (ed.). Spider Monkeys. Cambridge University Press. pp. 185–214. ISBN 978-0-521-86750-4.

Written by Breton Worthington, March 2024