Spider monkeys, belonging to the genus Ateles, are fascinating primates native to the tropical rainforests of Central and South America, ranging from Mexico to Bolivia and Brazil. These New World monkeys, with their disproportionately long limbs and prehensile tails, are well-adapted to their arboreal lifestyle. They effortlessly navigate the high canopy, captivating observers in zoos and nature documentaries alike. This article explores the dietary habits of these incredible creatures, shedding light on what they eat to survive and thrive in their rainforest homes.
Spider Monkey Overview
Spider monkeys are New World monkeys found in the jungles of the American continents, specifically in parts of Mexico, the Amazon rainforest, and Central America. New World monkeys are distinct from their Old World counterparts, being generally smaller with flatter noses. While New World monkeys tend to be small, the spider monkey is one of the largest among them. There are seven recognized species of spider monkeys, each with unique color patterns and physical distinctions. These species include:
- Brown-headed spider monkey (Ateles fusciceps)
- Red-faced spider monkey (Ateles paniscus)
- Peruvian spider monkey (Ateles chamek)
- White-cheeked spider monkey (Ateles marginatus)
- White-bellied spider monkey (Ateles belzebuth)
- Geoffroy's spider monkey (Ateles geoffroyi)
- Brown spider monkey (Ateles hybridus)
Sadly, all true spider monkeys are endangered, with the brown-headed and brown spider monkeys being critically endangered.
Spider monkeys belong to the family Atelidae, which includes some of the largest New World monkeys. The genus name Ateles translates to ‘imperfect’ in Greek, referring to their lack of opposable thumbs. However, this does not hinder their ability to thrive in their natural habitats.
On average, they weigh about 6 kilograms (13.25 pounds) and have a body length of 35 to 66 centimeters (14 to 26 inches). They also have long tails that can grow to lengths of 88 centimeters (35 inches). These tails are prehensile, which means they’re often used as a fifth limb for grasping. All of these physical traits contribute to spider monkeys being extremely agile and adept at swinging from tree to tree, allowing them to thrive in an arboreal (tree-based) lifestyle.
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General Dietary Habits
Spider monkeys are omnivores, but their diet consists mostly of plant matter. They are also considered frugivores because fruits constitute a significant portion of their food intake. Specifically, spider monkeys eat leaves, fruits, and nuts, foraging for these food sources in the rainforest canopy.
During the day, the spider monkey searches for fruit, which makes up the main part of its diet. They will also eat flowers, seeds, bark, leaves, and small insects during the dry season when fruit isn’t available.
Spider monkeys primarily sustain themselves on a diet rich in fruits. However, they also eat flowers, bark, seeds, leaves, and even insects. In times of limited food availability, spider monkeys will deviate from their normal diet even further, eating bird eggs, small animals, and honey. They spend most of the daylight hours climbing and swinging through the high canopy of trees.
Specific Food Preferences
Spider monkeys favor fleshy fruits, with leaves being their second most consumed food item. The brown spider monkey, for instance, has a diet that consists of over three-quarters lipid-rich fruits. However, in drier seasons when fruit is less abundant, it feeds on leaves, seeds, flowers, bark, honey, decaying wood, and occasionally insects such as termites and caterpillars. The brown spider monkey also feeds on different species of figs year-round.
Foraging Behavior
Spider monkeys start looking for food early in the morning and sleep in trees at night. They usually live in groups of 20 to 30, but groups of up to 100 have been seen in the wild. If they can’t find food at their memorized food sources, they’ll split up into small groups and go foraging. Usually, they hang out in a large troop of up to 100 individuals, but they break off in groups of about 5 when it’s time to hunt down a meal. Their foraging consists of carefully combing trees for their snacks.
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Spider monkeys spend much of their time resting (45%±1%). Black spider monkeys forage in the forest canopy by swinging to and from branches. They typically have two feeding periods a day, usually from 08:00 to 10:00 and from 12:00 to 14:30.
Adaptations for Their Diet
Spider monkeys have several adaptations that aid in their foraging and feeding habits. They have a prehensile tail, which means they can hang from tree limbs and grasp things with their tail. This tail is longer than their body length and is a dominant feature of theirs. They have long fingers which help them reach for small things like spiders or berries. They do not have a thumb, but this lack of dexterity is made up for by their tails which they’re able to use as an extra limb. Their fingers are also hook-like which aids them when they move around the trees looking for food.
Ecological Role
Beyond their personal sustenance, spider monkeys’ eating habits also play a significant ecological role. As they forage, they inadvertently aid in shaping the composition of their forest habitats, primarily through seed dispersal. As they move about the canopy, dispersing seeds through their droppings, they actively assist in the regeneration and health of their habitats. This seed dispersal is fundamental in maintaining the diversity and vitality of tropical forests and helps to ensure the continued propagation of tree species within their habitats. Black spider monkeys are important seed dispersers for various tree species.
Threats to Spider Monkeys and Their Diet
Unfortunately, human beings are the biggest threat to spider monkey populations. Deforestation has demolished huge swaths of their natural habitat which has decimated their numbers. Things like development and palm oil farms are turning their diverse habitat into a monoculture of trees that cannot sustain their populations. Habitat loss is ongoing within its wild range, and an estimated 98% of its habitat is already gone. Habitat loss is driven both by logging, and land clearance for agriculture and cattle ranches. It is also threatened by hunting (in some regions it is the favorite game) and the wild animals trade.
The inter-Andean forest is also diminishing due to mining, infrastructure, and other industrial reinforcements. In addition, their recovery from population loss is due to their low reproductive rate.
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Conservation Efforts
Conservation efforts such as alleviating the detrimental effects of fragmented landscapes on the brown spider monkey population are being pursued. The IUCN is a group that is aiming to protect and grow the spider monkey population. They are raising money to help create corridors that connect them to all of the fragmented land. A small population of fewer than 30 individuals has been discovered in a protected area of Colombia, the Selva de Florencia National Natural Park.
Interesting Facts
- Yes, spider monkeys eat spiders. They also eat insects, but half of their diet is fruit and nuts.
- Yes, spider monkeys get drunk when they eat overripe fruit. They’re not at risk of hurting themselves, however, since they stop eating the drunken fruit when they’re full. The alcohol content of rotten fruit is also much lower than the processed alcoholic beverages that adult humans drink.
- Yes, a spider monkey eats bananas, but it’s almost always in captivity. Bananas are not a natural food source that’s available in their environment. In fact, the banana that can be purchased from the grocery store can’t be found in the wild at all. The only time a wild spider monkey will eat bananas is if they happen to live near a banana farm.
The Brown Spider Monkey (Ateles hybridus)
The brown spider monkey (Ateles hybridus) is a critically endangered species. Like all spider monkeys, it has long, slender limbs and a long prehensile tail. The brown spider monkey has long and thin limbs with longer forelimbs than hind limbs. It has a distinctive 75 cm (30 in) long flexible, thin and prehensile tail which at times acts like a fifth limb. The tail has a highly flexible, hairless tip with skin grooves which improves grip. Brown spider monkeys have four curved fingers and lack thumbs to help them swing from one tree to another. These features make it possible for it to climb trees at high elevations, and hang and swing from one tree to another without often having to return to the ground.
Adult males weigh between 7.9 and 9.1 kg (17 and 20 lb) and adult females weigh between 7.5 and 9 kg (17 and 20 lb). Its average adult body length is about 35 to 70 cm (14 to 28 in). Its coloration ranges from light brown to dark on upper parts including the head. Its most distinctive characteristic is a whitish triangular forehead patch, although not all individuals have one.
Even though the brown spider monkey spends most of its time high in trees, it occasionally descends to eat soil and drink water. The brown spider monkey mainly forages in the forest canopy and relies mostly on its senses of sight, smell, taste, and touch to find food. It is mainly herbivorous and frugivorous.
Natural predators include jaguars (Panthera onca), mountain lions (Puma concolor), harpy eagles (Harpia harpyja), and crested eagles (Morphnus guianensis). Since 2004, the brown spider monkeys have been listed as one of the most endangered primates in Colombia's inter-Andean Valleys. This is due to habitat fragmentation, threats of hunting, and threats of capture for pet trade. The population is estimated to have decreased by at least 80% and some populations have already been extirpated.
The Black Spider Monkey
Black spider monkeys are native to South America, north of the Amazon River. They can be found in Brazil, French Guiana, Guyana, and Suriname. They have been studied in Peru and Bolivia as well.
Black spider monkeys have small heads, relative to their bodies. Black spider monkeys are arboreal.
Black spider monkeys spend much of their young lives with their mother. The baby is carried by the mother continuously, clinging to her body, which continues until 4 to 5 months of age. At about 5 months old it will ride on its mother’s back. Weaning takes place at around 2 years.
Black spider monkeys communicate in many different ways, which warns others of predators and clarifies where food can be found.
Black spider monkeys have an average home-range of 2.55 km^2. Black spider monkeys are important seed dispersers for various tree species. Black spider monkeys are listed as vulnerable on the IUCN Red List.