Callicebus coimbrai

Geographic Distribution and Habitat

Coimbra-Filho’s titi monkey (Callicebus coimbrai), or simply known as Coimbra’s titi, is native to Brazil, residing in the northeastern states of Bahia and Sergipe within heavily fragmented patches of Atlantic coastal forest. These sparsely occupied forest fragments vary in size from less than 0.02 square mile (0.05 sq km)—in Lamerão/Minas d’Água, Bahia, and Fazenda Riacho Seco, Sergipe—to the largest and southernmost fragment of 11.6 square miles (30 square km) in São Francisco do Paraguaçu in Bahia. The species’ geographic distribution, which once covered an overall area of about 11,583 square miles (30,000 square km), has been reduced to just 77 square miles (200 sq km)—less than 1 percent of its original range.

To the north, the species’ geographic distribution extends to the São Francisco River; to the east, a small forest along the Atlantic Ocean prevents the species from reaching the coast; to the south, the species is found on the north bank of the lower Paraguaçu River, which serves as a demarcation boundary from the coastal black-handed titi monkey (Callicebus melanochir), who resides on the river’s south bank. Farther west, another “titi cousin” shares the region of Feira de Santana with Coimbra-Filho’s titi monkeys. Barbara Brown’s titi monkey (Callicebus barbarabrownae), commonly referred to as the northern Bahian blond titi, resides along both the north and south riverbanks of the Paraguaçu. No physical barrier separates the Coimbra-Filho and Barbara Brown titi species; rather, a 31-mile (50-km) ecological barrier appears to naturally delineate the separate populations by their respective habitat preferences. Barbara Brown titis prefer the drier forests and semi-arid, tropical vegetation to the west; while Coimbra-Filho’s titis prefer the humid Atlantic Forest to the east where they reside in tropical, edge, lowland, and evergreen forests, typically at elevations of 9.8–26 feet (3–8 m) above ground, with the highest recorded elevation of 984 feet (300 m).

Although Coimbra-Filho’s titi monkeys are able to tolerate and survive highly disturbed areas that include cattle ranches, agricultural plantations, and expanding urban infrastructure (human settlements, roadways, and power lines), their natural—and preferred—habitat is densely wooded areas. Sadly, forestland continues to be destroyed, making the species’ continued survival precarious.


Researchers recognized Coimbra-Filho’s titi monkey as a distinct species in 1999, after analysis of five specimens collected from three sites within Sergipe’s Atlantic Forest corroborated findings from earlier craniometric studies (skull measurements). Previously, the species had been considered a subspecies of the Atlantic titi monkey (Callicebus personatus).

Today, Coimbra-Filho’s titi monkey is regarded as one of five species within the Callicebus genus. Besides the Atlantic titi (its former “parent”), three other species share this genus: Barbara Brown’s titi monkey, the coastal black-handed titi monkey, and the black-fronted titi monkey (Callicebus nigrifrons). Coimbra-Filho’s titi has no “children,” or subspecies.

Coimbra-Filho's titi range, IUCN 2022

Size, Weight, and Lifespan

Sexual dimorphism (a distinct difference in size or appearance between the sexes in addition to difference between the sexual organs themselves) is not pronounced in these little primates. Thus, while measurements are available only for the female of this species, both males and females appear to be the same size. Head-to-body length is typically between 13–14 inches (33–36 cm), and they have lengthy hind limbs. A nonprehensile tail adds another 18–19 inches (46–48 cm) to their small frame. Adults weigh a mere 2.2 pounds (1 kg), on average.

In the wild, titi monkeys live into their early 20s, barring any harm or death suffered related to anthropogenic (human) activities. Captive titi monkeys have been reported to live beyond 25 years.


Adult male and female Coimbra-Filho’s titis are indistinguishable in appearance. A dark, little face with deep, brown eyes and a flat muzzle characterized by widely spaced, sideways-flaring nostrils is overwhelmed by a wild, buff-colored mane that somehow fails to conceal its dark ears. A crazy, furry, black coif decorates the crown of the Coimbra-Filho’s titi monkey’s head. Covering the tiny body is a scruffy, cinnamon-colored pelage, accented by a striped pattern beginning along the upper back that leads to a long and furry orange tail. Hands and feet are black.

Their physical characteristics help to distinguish Coimbra-Filho’s titi monkeys from their cousins, Barbara Brown and coastal black-handed titi monkeys, who have lighter-colored faces, reddish or darker manes, and a more grayish pelage with a flecked (rather than striped) pattern along the back. The shape and size of its skull and differences in dentition (teeth) further distinguish Coimbra-Filho’s titi monkey from its titi cousins in the genus Callicebus.

Photo credit: Paiivaleiite/Creative Commons

These small monkeys are primarily herbivores, or plant eaters. They eat mostly fruits (making them largely frugivorous), though they are not overly selective about which fruits they eat from their tropical habitat. Leaves, particularly young leaves and leaf buds which are high in protein, are another important dietary staple (so these primates are also folivorous). Woody liana vines provide fruits, leaves, and flowers as food sources. Their short canine teeth allow the titis to easily graze on fruits and foliage. Seeds and the occasional insect complement the Coimbra-Filho’s titi monkey’s meal plan. During the dry season when fruits are scarce, insect consumption (especially caterpillars) increases. Nursing mothers also eat greater amounts of insects, as their protein requirements increase during this period.

An unlikely delicacy may be baby birds. Yes, birds. Researchers conducting a field study in March 2014 in Sergipe observed a subadult Coimbra-Filho’s titi monkey prey upon and eat a nestling pale-breasted thrush (Turdus leucomelas). The individual grabbed the baby bird with his right hand and moved about 3.2 feet (1 m) away from the nest to eat it. The next day, the same individual captured and ate another nestling pale-breasted thrush. He was also observed robbing and eating eggs from the nests of unidentified bird species. These events occurred within the largest fragment of Sergipe’s Mata do Junco Wildlife Refuge and mark the first time that predation of birds has been recorded in the species, or for titis in general.

The juicy fruits that Coimbra-Filho’s titis eat provide them with their daily water requirement.

Behavior and Lifestyle

Coimbra-Filho’s titi monkeys are arboreal; that is, they spend the majority of their lives in trees, favoring the lower to middle forest strata (or layer), also referred to as the forest understory. In this warm, damp, and sheltered environment that consists of small trees and shrubs that grow between the forest canopy and forest floor, the titis advance through their habitat slowly and purposefully, using all four limbs (quadrupedally). Occasionally, they leap from tree to tree. Their long tail, though incapable of gripping, helps them to balance. While eating, the titis sit upright on branches and tree trunks. Individuals from a family group often eat together from the same food source, leading researchers to speculate that sharing a meal is a social activity, not solely about sustenance. Titi monkeys have been observed chewing leaves and then rubbing the pulp (or pith) on their chest. The reason for this behavior is unknown.

Titis only descend to the ground if they must—to cross gaps in forest patches or to seek alternative food resources, a necessary adaptation to scarce arboreal fruit availability, wildlife biologists believe. When on the ground, the titis move quickly, clambering forward. Younger titis might take this ground opportunity to play with one another.

During the warmer months, when fruits are plentiful, the titis rise before dawn (unless it’s raining) to begin their day of foraging. During the colder months, when fruits are scarce, they sleep in, rising up to 4 hours after sunrise. (Who wants to get out of their warm bed when it’s cold outside?) They forage until midday, when they take a generous nap before resuming their activities.

In fact, naps are important to this titi species, and these monkeys spend a considerable amount of time each day resting quietly in dense vegetation. But they can’t afford to be too lax, because predators lurk. Raptors are their foremost predators and include the Guianan crested eagle (Morphnus guianensis), ornate hawk-eagle (Spizaetus ornatus), and turkey vulture (Cathartes aura). The tiny monkeys are also preyed upon by larger primates, such as the yellow-breasted capuchin monkey (Sapajus xanthosternos).

In a field study, wildlife biologists observed the titi monkeys’ behavior in response to a threat by a yellow-breasted capuchin. The titis emitted a quiet vocalization, alerting group members of the threat, then descended to the dense undergrowth to avoid detection and predation. In another field study, in response to a threat by a turkey vulture, while they were feeding from a fruit tree, the titis jumped to the forest floor to escape.

Both these antipredator behaviors have been documented for other Latin American primates and, with regard to titi monkeys, add to our understanding of how these primates adapt to threats within their fragmented habitats.

Titis also practice crypsis—the art of camouflage—to avoid predator detection. Hiding in the dense foliage and tangled vines, they blend in with their environment.  

Coimbra-Filho’s titi monkeys usually end their traveling and foraging activities before sunset (likely a predator avoidance strategy). Overnight, they sleep together in the tangles of a tall, vine-encrusted tree and often return to the same tree each night. Besides providing the titis with an important food source, liana vines attach themselves to tree trunks and branches, thereby linking trees together to provide shelter and canopy-to-canopy access to the titis.

Fun Facts

While the zoologist Shuji Kobayashi is credited with its discovery, the species is named after Adelmar F. Coimbra-Filho, founder and Former Director of the Rio de Janeiro Primate Centre, in honor of his work in the field of Brazilian primatology and biology.

Daily Life and Group Dynamics

A typical Coimbra-Filho titi family group is composed of a breeding pair of adults and their immature offspring from several seasons. The adult breeding male serves as the group’s leader. Group size ranges from 2 to 8 individuals, with 2 to 4 individuals being most common. Juveniles, both males and females, leave their family group at between 2 to 3 years of age (when they reach sexual maturity) with the hope of finding a mate. Wildlife biologists have documented one instance of a dispersed male who returned to his natal (birth) group one year after he emigrated. (Apparently, he had been unsuccessful in finding a mate.) After being met with initial antagonism by the lead breeding male, the deflated male was accepted back into the group (a situation perhaps similar to young adult human primates who return home after failing to strike out on their own).

Home range for this highly territorial species varies according to the size of forest fragment where they live. Thus, home range size might be as little as 4.9 acres (2 hectares) in smaller forest fragments to 49 acres (20 hectares) in larger fragments. These titis typically cover from 0.43 to 0.68 mile (0.69–1.1 km) in their daily travels.

Other primate species who share habitat with Coimbra-Filho titis include marmosets (Callithrix), tamarins (Saguinus), squirrel monkeys (Saimiri), saki monkeys (Pithecia), capuchins (Cebus), owl monkeys (Aotus), howler monkeys (Alouatta), woolly monkeys (Lagothrix), and spider monkeys (Ateles).

Nonprimate species include the maned sloth (Bradypus torquatus), the Brazilian three-banded armadillo (Tolypeutes tricinctus), Burmeister’s leaf frog (Phyllomedusa burmeisteri), and the hoary fox (Lycalopex vetulus).


Titi monkeys are more vocal than other Latin American primates and their vocalizations are more complex. When faced with a threat or during an aggressive encounter, they emit high-pitched squeaks; when they are just chatting amongst themselves or in friendly, social situations, they emit low-pitched squeaks. Soft chirps and whistles are sounded as they move through their forest habitat. Trills, grunts, and groans are also part of their vocalization repertoire. Their loud territorial call, intended to identify and protect their area, can be heard up to 1.6 miles (1 km). While this call is meant to be intimidating to potential intruders, the titis rarely engage in battle.

Coimbra-Filho’s titis, like other titi monkey species, are known for their vocal duets, with the adult breeding male and female couple singing alternate musical notes to one another, reinforcing and celebrating their bond. These duets occur at daybreak but can also occur during the course of the day in response to vocalizations from neighboring titi groups. Occasionally, other family members join in, adding their own musical notes.

The practice of interweaving their tails together, while sitting closely side by side, further helps to strengthen the bond between an adult male and female breeding couple. Tail entwining occurs whether the couple is resting or sleeping.

Grooming serves as an important tactile activity that strengthens social bonds among all members of a family group. The monkeys often engage in mutual grooming sessions (allogrooming) during their rest breaks. An adult male is particularly attentive to his female breeding partner, grooming her frequently.

Olfactory communication appears to have socioecological importance in titi species, but scientists are only beginning to study this behavior. A study in the July 2021 International Journal of Primatology reports on findings of two Coimbra-Filho’s titi groups. Researchers recorded 14 instances, 11 involving males and 3 involving females. The titi rubbed his/her right hand along his chest, stimulating large glands to release an odorous secretion. The titi then repeatedly wiped his/her palm on a nearby branch. The context in which this olfactory event occurred was most often sexual, followed by encounters with outside groups related to territorial defense.

Reproduction and Family

Like other titi species, Coimbra-Filho’s titis are monogamous creatures; that is, the adult breeding pair mates for life, taking no other partners. Breeding appears to be seasonal for this species with births occurring in the early dry season, October through January. After a gestation period of about five months, the female gives birth—usually to a single infant, though twin births sometimes occur. Survival of both twins depends on the care offered by other family members.

Except for a mother’s crucial role in nursing her young, a father is the primary caregiver and protector. He carries his young infant (or infants, if twins) throughout his daily activities, making the time to play with and groom his progeny, returning the infant(s) to the mother when time to nurse. Infants are considered weaned at five months of age, and by age 2 they are fully matured (able to reproduce).

Photo credit: ©DanielBranch/iNaturalist/Creative Commons
Ecological Role

Thanks to their largely frugivorous diet, Coimbra-Filho’s titis monkeys help to regenerate their habitat by dispersing the seeds of the fruits they eat, via their feces, during their daily travels.

Conservation Status and Threats

The Coimbra-Filho’s titi monkey is classified as Endangered by the International Union for Conservation of Nature (IUCN, January 2015), appearing on the IUCN Red List of Threatened Species. The species is considered one of the most Endangered of all Latin American primates. One estimate puts the overall total wild population at less than 2,500 mature individuals, with fragmented subpopulations containing less than 250 individuals. Another estimate put the overall number at much less, with only 500 to 1000 individuals remaining.

The biggest threat to Coimbra-Filho’s titi monkeys’ survival is habitat loss. Anthropogenic activities that include logging, human infrastructure (settlements and roadways), and the conversion of pristine tracts of forest to farmland for cattle grazing have nearly wiped out the species’ habitat. The remaining isolated and disturbed forest fragments negatively impact the size of breeding populations by limiting genetic diversity. And the titis face greater risk of predation when they are forced to move from one forest fragment to another, leaving themselves vulnerable and exposed. Any further disturbance in their already drastically reduced range jeopardizes the species’ ability to thrive and survive.

Additional threats to the species include being run over by vehicles, electrocution from newly erected power lines, predation by domestic dogs, and sporadic hunting (because of Coimbra-Filho’s titi monkey’s small size, the species is not overly hunted).

Conservation Efforts

Coimbra-Filho’s titi monkey is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival. With the goal of reducing pressures on the remaining Coimbra-Filho’s titi population, Brazil has implemented some measures of protection at the federal, state, and municipal level. One of the more significant measures restricts the establishment of new rural human settlements and regulates related licensing for infrastructure (such as gas pipelines).

In 2003, the species was placed on Brazil’s Official List of Threatened Fauna. Overseen by the Committee for the Conservation and Management of the Primates of the Northern Atlantic Forest and Caatinga, the organization is responsible for studying the current status and threats to the species, as well as developing and managing a plan for the species conservation.

The Refúgio de Vida Silvestre Mata do Junco (Mata do Junco Wildlife Refuge) was established in December 2007 by the Sergipe state government, with the specific aim of protecting remaining populations of Coimbra-Filho’s titi. A small number of privately owned reserves protect remaining habitat patches for the species.

In 2011, the National Center for Research and Conservation of Brazilian Primates helped establish the National Action Plan for the Conservation of Northeastern Primates, creating conservation strategies for five species, including Coimbra-Filho’s titi monkey. The overarching goals of this plan were to protect remaining habitats and create environmental corridors between populations. Several studies were conducted to better understand the risks and the use of space by Coimbra-Filho’s titis in severely fragmented landscapes.

No captive breeding programs are in place for the species.

Fast forward to 2023, with the species inching toward possible extinction, conservationists have sounded the alarm that we need to do much more to save these small monkeys from vanishing from our world.


Written by Kathleen Downey, December 2023