Geographic Distribution and Habitat
Once thought to be a subspecies of the cotton-top tamarin (Saguinus oedipus), Geoffroy’s tamarin (Saguinus geoffroyi) is recognized today as its own species. Known by the aliases Panamanian tamarin, red-crested tamarin, and rufous-naped tamarin, Geoffroy’s tamarin is a small New World monkey native to Panama and Colombia. Its range may have once included Costa Rica; however, the species has not been confirmed in that country since a rare (and speculative) sighting in the mid-1930s along the Panamanian border.
In Panama, Geoffroy’s tamarins are most abundant along the Pacific coast. On the country’s Atlantic coast, they are restricted to a small area along the Isthmus of Panama (a narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America), residing near the city of Colón and Lake Gatún within forests that have been almost completely destroyed by human activity. The monkeys also occur in central Panama.
Extending their range into northwestern Colombia, Geoffroy’s tamarins live along the Pacific coast, as far south as the Rio San Juan. Other populations live in an area surrounding National Natural Park of Las Orquideas, near the village of Mandé, Antioquia, at elevations as high as 3,281 ft (1,000 m), furthering their range to the west of the upper Río Cauca.
Diverse forest types provide Geoffroy’s tamarins with their habitat; these forests include primary, disturbed secondary, scrub (with shrubs and tall grasses), dry deciduous, and moist tropical rainforests. The monkeys prefer dense foliage and avoid open forest and open grassy areas.
The Geoffroy’s tamarin has the distinction of being Panama’s smallest monkey and the only tamarin species native to Central America. Even smaller species of monkeys are thought to inhabit some of Colombia’s forests.
About the size of a common squirrel, average head-to-body length is 8-11.5 in (20-29 cm). The monkey’s tail adds another 12-16.5 in (31-42 cm) to its diminutive body. Females weigh slightly more than males, with an average weight of 1.1 lb (0.51 kg). Males weigh about 1 lb (0.48 kg).
The monkeys’ thumbs are non-opposable and they are fitted with modified claws, rather than nails, on each digit except for the first digit on each toe. Like all tamarins, their canine teeth are larger than the incisors.
Average lifespan for captive Geoffroy’s tamarins is 13 years.
A white cottony, triangular Mohawk blazes the top of this tiny monkey’s head. The short fur on either side is black, giving greater prominence to the Geoffroy’s tamarin’s hipster hairdo. Reddish fur cloaks the back (or “nape”) of the neck.
Long, wispy white strands of hair extend from just beneath the temples of a hairless, chubby-looking black face. Brown eyes assess the world, and tiny scalloped ears listen to the sounds of the forest.
A black-brown-yellow mottled fur coat cloaks the body. The fur on the monkey’s chest and underside is white. Its tail matches the color of its nape and is accented by a black furry tip.
Newborns are covered in black fur, accented by a beige blaze. Their hairless faces are white.
Geoffroy’s tamarins are omnivores whose dietary medley includes fruits, flowers, insects, small rodents and reptiles, eggs, exudates (tree gums, saps, and resins), and plant greens.
Favorite fruits include mango, berries, guava, and the exotic, sweet fruit of the Annona spraguei tree. Fruits and flowers of the tropical Cecropia tree are also enjoyed. Large grasshoppers are a vital insect staple. The flowering cashew tree Anacardium excelsum provides Geoffroy’s tamarins with their favorite exudates, and the Enterolobium cyclocarpum, or “elephant ear” tree, provides plant greens along with sap.
Theirs is a seasonal menu. For most of the year, Geoffroy’s tamarins feed primarily on fruits. Insects are eaten mostly during the early wet season. But when fruits and insects become scarce, during the driest months of the year, nectar and exudates provide the monkeys with their sustenance. During the dry seasons the monkeys show a decrease in body weight due to loss of fat reserves.
Different field studies of the species place greater or lesser emphasis on the percentage of each menu item consumed, though fruit is always a major dietary staple.
Behavior and Lifestyle
Geoffroy’s tamarins are most active during daylight hours, making them “diurnal.” They become fully active about 45 minutes after full daylight. Although they spend most of their time in trees, making them an arboreal species, they occasionally venture to the ground to forage for certain foods or to access certain trees they otherwise cannot reach.
They travel about 1.28 mi (2.06 km) each day. They are vigilant when it comes to demarcating their home range, which can vary from 23 acres to 79 acres (9.4-32 ha), depending on the abundance and distribution of seasonal resources. Each morning, individuals visit and scent-mark the border of their range. Both males and females perform this task. Because females are fitted with much larger suprapubic glands (located above the pubic bone), they engage more frequently in scent marking. Males assume the role as border sentries; should a territorial encounter or dispute arise with another group, they act as the aggressors (despite the female dominance dynamic) to protect their group’s range. Males of neighboring territories are known to chase one another back and forth across the border that they share.
Daily Life and Group Dynamics
Geoffroy’s tamarins live in social family groups of 2 to 20 individuals, with 3 to 5 being the most common group size. Larger groups include both extended family and nonrelated members for a multimale/multifemale generational composition. Adults of both sexes migrate between groups. In what might appear to be a role reversal among many monkey species, Geoffroy’s tamarins are led by a group’s eldest female.
Fighting between males of different groups may result in lacerations, claws ripped from fingers and toes, and trauma (such as broken tails) sustained from falls 66 ft (20 m) to the forest floor. These altercations are most common during breeding season and usually occur at the borders of smaller home ranges.
Daily activity includes foraging, along with time spent resting and grooming. They move through the trees quadrupedally (on all four limbs) with horizontal bounds and gallops and, sometimes, impressive leaps. Spreading wide all four limbs and fully extending their tail, they leap distances of 16 ft (5 m) or more between trees.
Their non-prehensile tail helps them to balance as they reach for fruits. They might coil their tail beneath themselves as they enjoy their picked fruits, which they drop directly into their mouth. The monkeys find their insect snacks in the leafy lower canopy and shrub layer of the forest.
When it comes to foraging, Geoffroy’s tamarins are savvy opportunists. Their diet is similar to Panama’s tyrant flycatcher birds, with whom the monkeys share similar vocalizations. By tuning into these birds’ calls, Geoffroy’s tamarins are able to locate their favorite foods.
Although they avoid vertical descents, Geoffroy’s tamarins cling vertically with their claws embedded into the bark of a tree while feeding on exudates. Because their teeth are not adapted for gouging tree bark, they only eat easily available exudates, such as oozing sap.
Overnight, the monkeys rest in the safety of the tree tops. They seek out trees 32 ft (9.7 m) or more in height that are densely foliated and heavily vined to help conceal their presence from predators. Geoffroy’s tamarins have not been observed building nests themselves; instead, they sleep in nests that have been created, and vacated, by squirrels. They change their sleeping sites often.
Geoffroy’s tamarins’ tiny size makes them vulnerable to predators, who include wild cats, coatimundis (members of the racoon family), snakes, raptors, and, of course, humans. Should they encounter a potential predator, they “sound the alarm” through a variety of bird-like calls that serve as warning to other group members.
Communication consists of vocalizations, olfactory cues, and posturing.
Vocalizations include a variety of calls: The long whistle is a long-distance intragroup call used by individuals to locate one another; the soft long whistle is used by individuals just before contact with another group; long rasps are used during violent encounters; a loud long call is used during territorial defense; soft long calls are used to call members of a group together; and bird-like trills are alarm calls used to warn others in the group of potential predators.
Olfactory clues are given through scent marking. To claim a trail as their own, particularly when their range overlaps with another group’s trails, the monkeys scent-mark the tree branches that they travel upon. Geoffroy’s tamarins engage in two types of scent marking:
- Circumanal marking: An individual rubs its anal region (circumanal area) on a surface (such as tree branch) while in a sitting position; this is the most frequent marking behavior for the species.
- Suprapubic marking: An individual presses its suprapubic gland (located above the pubic bone) against a surface and deposits secretions by then pulling its body along the surface.
Posturing includes intimidation tactics: Scowling, piloerection (allowing the body hair to “stand on end” for the illusion of a larger body size), standing on hind legs, and tongue flicking are used during aggressive encounters.
Polyandry (a pattern of mating in which a female animal has more than one male mate) appears to be the primary mating system for Geoffroy’s tamarins; however, polygyny (a pattern of mating in which a male animal has more than one female mate) and monogamy (a mating system in which a male and female mate exclusively with each other) have also been observed in some groups.
Geoffroy’s tamarins reach sexual maturity (capable of siring and reproducing offspring) at about 2 years old. Mating season occurs primarily during January and February. To attract a male partner, a female may signal her willingness to mate by rapidly coiling her tail. Then she’ll do it again (because she is polyandrous, or promiscuous, depending on one’s viewpoint).
The gestation period is thought to be similar to that of the cottontop tamarin, 140 to 145 days (almost 5 months). Births occur from March through June, peaking between late April to early June.
A single infant or twins can be born. Twins are common, although one of the twins often dies within the first few months of life. The interbirth period ranges between 154 and 540 days, with an average of 311 days. The longer interbirth periods occur after twin births.
Newborns weigh only 1.4-1.8 oz (40-50 g). They become mobile at 2 to 5 weeks of age and begin eating solid food at 4 to 7 weeks old. At 10 to 18 weeks, they are independent and are considered fully weaned at 15 to 25 weeks.
Males help out with infant care, whether or not they are the parent; without a paternity test, they have no way of being certain that they sired the offspring! As the infants’ mothers do, the males carry infants on their back and help groom them. (Carrying the young for the first six to eight weeks of life helps to establishes familial bonds.) Older siblings might also help out with child care.
Thanks to their penchant for fruit, Geoffroy’s tamarins are helpful habitat regenerators: the seeds they distribute, via their feces, encourage new plant growth. Thanks to their penchant for grasshoppers and other crop-eating insect pests, these monkeys are efficient pest controllers.
Geoffroy’s tamarin is listed as Near Threatened by the International Union for Conservation of Nature, appearing on the IUCN Red List of Threatened Species (IUCN, 2015). Scientists anticipate a population reduction of 25% or more over the course of the next three generations (18 years). A reduction of this size will likely result from a combination of forest loss (the rates of which have effectively doubled throughout its range in Panama and Colombia during the course of the last generation), to an ongoing, unregulated pet trade, for which this small monkey is a favored species, and mortality due to automobiles in regions of its range that are becoming more heavily populated.
Altered habitats have had both a positive and negative impact on the species. Geoffroy’s tamarins thrive in secondary forests, including forestland that has been clear-cut for agricultural purposes and then abandoned. Unfortunately, they are also easily hunted in these altered habitats. The monkeys are trapped, kidnapped, and sold into the pet trade.
Besides the trauma of being kidnapped, monkeys do not fare well as pets. Their specific enrichment needs cannot be adequately met, and they are put at risk of contracting human diseases. For example, Human herpesvirus 1, which typically causes cold sores or fever blisters in a human host, can act as a “killer virus” when crossing the species barrier to New World monkeys.
The Geoffroy’s tamarin is listed in Appendix I of the Convention on International Trade in Endangered Species to ensure that international trade in specimens of wild animals and plants does not threaten their survival. No conservation efforts specific to the species are evident.
The monkeys’ presence inside national parks, both in Panama and Colombia, may offer them a modicum of protection from nefarious human activities. Increased public education and fully protected refuges would help ensure that these monkeys have the opportunity survive and thrive.
Written by Kathleen Downey, November 2018