Coastal Black-Handed Titi, Callicebus melanochir
COASTAL BLACK-HANDED TITI
Callicebus melanochir
Geographic Distribution and Habitat
The coastal black-handed titi, also known as the black-handed titi and Southern Bahian masked titi, is local to the coastal forests of the Brazilian Atlantic coast. Specifically, their range extends from the southern part of the Brazilian state of Bahia to the northern part of the state of Espírito Santo, or between the Mucuri and Paraguaçú rivers.
Within this range, the coastal black-handed titi has been known to inhabit cabruca, which are cacao plantations shaded by native trees located in human settlements, such as the cities of Ilhéus and Itabuna. As a coastal species, the elevation of their habitat ranges from 656-984 feet (200-300 m).
Size, Weight, and Lifespan
The coastal black-handed titi ranges in head-to-trunk length from 11-18 inches (29-45 cm) and can reach a weight of up to 3.5 pounds (1.6 kg). Their tail adds 10-22 inches (26-56 cm) in length.
The lifespan of most titi monkeys has not been clearly determined, but those in the genus Cheracebus (one of three genera of titi monkeys, but not that of the coastal black-handed titi) may live up to 12 years in the wild.
Coastal black-handed titis are sexually dimorphic, meaning there are noticeable physical differences between genders. Males are larger when compared to females, although females’ tails are longer than those of males. Additionally, females have lighter coloration on the inner parts of their limbs, chest, and abdomen.
Appearance
The coastal black-handed titi is covered in fluffy, dense grey or grey-brown fur. Their long and bushy non-prehensile tail (which cannot be used for grasping) is used instead as an aid in balancing among the tree branches. Thanks to a dense layer of fur, their bodies appear to be more round and stout than is actually the case.
Their face, hands, and feet are black in color, while their eyes are brown.
Diet
The coastal black-handed titi is primarily frugivorous, with fruit making up over half of their diet. They have also been known to consume seeds, flowers, young and mature leaves, dirt, and insects, however not at the same rate as delicious, fleshy fruit!
Behavior and Lifestyle
The coastal black-handed titi is diurnal (active during the day), primarily arboreal (tree-dwelling), and travels around their habitat on all fours or by jumping.
Limited studies of the coastal black-handed titi, as well as studies of related titi species, have shown that coastal black-handed titis spend much of their time resting (40% of total activity time according to one study group), followed by traveling throughout their habitat (32%) and foraging and feeding (27%). Only about 1% of their time is dedicated to social behavior.
As is true of other titi species, the coastal black-handed titi is known to be aggressive toward rival groups. They maintain territorial boundaries through the use of loud vocalizations.
Besides humans seeking bushmeat, other potential predators of the coastal black-handed titi include raptors such as Harpy eagles, cats, and snakes. While the raptors patrol the skies, cats, and snakes are primarily found on the forest floor. To avoid these predators, coastal black-handed titis spend the majority of their time in the trees. Their thick fur layer provides them with a form of camouflage, allowing them to be mistaken for growths on tree branches. This helps serve as protection from predators.
Like its “cousin” the Atlantic titi (C. personatus), the coastal black-handed titi is geophagic (dirt-eating). Scientists are still trying to determine why this is done.
The call of the coastal black-handed titi is unlike that of any other primate in the region, and can be heard for miles!
As is common to titi species in general, the coastal black-handed titi is monogamous (having one mate), and lives with a single partner for life. They live in family groups ranging between 4-6 individuals which are made up of the breeding pair and their immature offspring. A group’s fixed home range spans between 54.4 and 59.3 acres (22-24 ha).
Upon waking up in their sleeping tree, coastal black-handed titis will engage in song-like vocalizations, which are likely intended to announce their presence and to maintain territorial boundaries between neighboring groups. Interactions between rival groups may be aggressive, so these vocalizations play a role in helping to maintain the peace by allowing the various groups to maintain an acceptable distance from one another.
After these morning calls have concluded, the family forages for food, taking rest breaks in between foraging sessions. The average range through which they travel during the day is approximately 0.62 miles (1 km). Once foraging for the day has finished, the family retreats to their sleeping tree for the night. Similar to the Atlantic titi, the coastal black-handed titi likely does not construct a sleeping nest. Instead, they gather on a large open bough. In addition, when resting, the coastal black-handed titi is believed by scientists to “tail twine”, or wrap their tails together. This is a behavior displayed in times of both stress and contentment, and titi monkeys often wake up with a spiral “bed head” on their tails from twirling throughout the night.
The main form of communication for which the coastal black-handed titi is best known is their “dawn call.” This shared serenade is performed by the breeding pair and can last from a minute up to an hour. Scientists speculate these calls are part of the effort to maintain territorial boundaries between neighboring groups by warning others to keep their distance, as the coastal black-handed titi is defensive, territorial, and may be aggressive toward rivals.
Other types of coastal black-handed titi vocalizations have not been extensively studied. However, some primatologists have speculated that the coastal black-handed titi may engage in vocalizations that have been observed in another “cousin” species, the Coimbra-Filho’s titi (C. coimbrai). This species has been known to emit long, whistle-like, high-pitched, squeaky alarm calls to ward off predators, as well as low-pitched, canary-like chirps for exchanges among members of the family group. Groans, grunts, and trills have also been documented as part of their vocalization repertoire.
Not much is known regarding the mating rituals of the coastal black-handed titi. Females have a gestation (pregnancy) period of five months, and give birth between August and October. The number of offspring born after each gestation period is unknown, but like the Atlantic titi, females most likely give birth to a single offspring.
As is common in other titi species, due to the certainty of paternal identity (thanks to their monogamous lifestyle), the father is the primary caretaker for the offspring. He is responsible for carrying his offspring around the habitat, grooming them, socializing with them, and preparing them for adulthood. The mother’s only responsibility for the young consists of nursing them. Infant coastal black-handed titis will cling to the dad for the first six months of life. As they mature, they become more mobile and wander close to their parents, as well as partake in the nightly tail twine alongside the rest of their family.
Weaning from mom’s milk occurs at five months of age. On average, other titi species reach independence at around two years of age. This may also be the case for the coastal black-handed titi. Upon reaching maturity, the offspring leave to start groups of their own.
Thanks to their diet consisting of fruits and seeds, the coastal black-handed titi aids in the spread and rejuvenation of the forest by dispersing seeds through their feces as they move about their habitat. As they sometimes supplement their main diet with flowers, the coastal black-handed titi may also serve as a pollinator. Similar to butterflies and bees, they collect pollen from flowers while drinking nectar. They then deposit the pollen on other flowers they visit along their journey through the habitat. The role of the coastal black-handed titi is critical to the process of forest restoration. This is helpful in making up for the ongoing shrinkage and degradation of the Brazilian Atlantic forest which has resulted from agricultural conversion, deforestation, and wildfires.
The International Union for Conservation of Nature lists the coastal black-handed titi as Vulnerable (IUCN, 2015), appearing on the IUCN Red List of Threatened Species.
The coastal black-handed titi (along with other titis) inhabits the most developed and populous regions of Brazil. As is common in developed areas, the region has suffered from extensive habitat loss and fragmentation, which in turn is the top threat to the coastal black-handed titi’s survival. This reduction in forest habitat is primarily due to pressures to increase agriculture and cattle ranching. Given the coastal black-handed titi’s small size, hunting for local bushmeat consumption is a minimal to moderate threat in comparison.
The coastal black-handed titi 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.
The coastal black-handed titi is found in a number of protected areas, including (but not limited to): Una Biological Reserve, Pau Brasil National Park, Monte Pascoal National Park, Rio Preto National Forest, and Córrego do Veado Biological Reserve.
Conservation action steps need to include properly enforced land and water management, and proper management of areas in which the coastal black-handed titi is found. The coastal black-handed titi is a species in dire need of more research. Specifically, additional monitoring of their population trends is needed, along with further research on their population size, distribution, and trends, as well as in life history, and ecology. Such research, along with conservation actions will hopefully prevent the coastal black-handed titi from creeping further along the path to extinction.
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Written by Sienna Weinstein, March 2024