Callicebus personatus
masked titi

Masked titis are restricted to Atlantic coastal forests of Brazil (Nowak 1999). They live only in the southeastern Brazilian states of Bahia, Espirito Santo, Minas Gerais, Rio de Janeiro and Sao Paulo (Kinzey 1983). There are five subspecies which occupy distinct portions of this area (Wisconsin Regional Primate Research Center, 2001). Callicebus personatus is allopatric with the C. moloch and C. torquatus (Kinzey and Becker 1983).

Masked titis occur in low densities in widely scattered forests (Nowak 1999). They inhabit primary and secondary Atlantic coastal forests from sea level to 1000m (3281ft); and are also found in banana groves (Rowe 1996). They may prefer secondary forests with thick understory growth (Wisconsin Regional Primate Research Center, 2001)

Masked titis are represented by 5 distinct subspecies, each with their own color patterns (Wisconsin Regional Primate Research Center, 2001). In general they have black foreheads and sideburns. Their bodies are covered with thick soft grayish to yellowish orange fur. They have a small rounded head and somewhat flattened, high face (Nowak, 1999). The nonprehensile tail is well furred and is the same color as the body, but mixed with black. Hands and feet are black (Rowe, 1996).

Body length: Female 310 – 400mm, Male 350 – 420mm; Tail Length: Female 418 – 560 mm, Male 470 – 550; Weight: Female 970 – 1600g, Male 1050 – 1650g (Rowe, 1996). Dental formula is 2/2 1/1 3/3 3/3 = 36 (Wisconsin Regional Primate Research Center, 2001). The first upper incisor has a bluntly pointed cutting edge. The second upper incisor is staggered behind the first. The molars are heavy and brachyodont with high, sharp cusps (Nowak, 1999).

Longevity of C. personatus is unknown in the wild. However, a captive individual of a closely related species (C. moloch) lived to at least 25 years of age.

Masked titi monkeys are diurnal and arboreal forest dwellers (Nowak, 1999). They spend at least half of the active day resting, 2 to 3 hours feeding, and less than 20% of the day traveling (Kinzey and Becker, 1983). Their average active day, from first movement to time first individual reaches its sleeping position for the night, is 11.5 hours (Kinzey and Becker, 1983).

Titis live in family groups comprised of a male and female pair and their offspring, usually 2 to 7 individuals (Nowak, 1999). They sleep huddled, with tails entwined, in branches 25 to 40 meters high in large trees above the canopy (Kinzey and Becker, 1983; Rowe, 1996). In their usual sleeping position the body is extended and the side of their head rests in their folded hands (Nowak, 1999). Titis leave their sleeping tree at dawn and return in late afternoon (Muller et al., 1997). Adult males are usually always the last to leave the sleeping tree (Kinzey and Becker, 1983).

Normally masked titis do not descend to the forest floor. They have only been observed moving below a height of 5m during less than 1% of their daily activity period (Muller, 1997). Titis are quadrapedal. When walking on all four limbs the body hunches, rotating the hind limbs outward. The characteristic resting position is the hunched body with all four limbs brought together on the branch as the tail hangs down vertically. From the resting position, a titi monkey can jump by rapidly expanding the hind limbs while it stretches its arms outward to enable the hands to grasp another branch (Nowak, 1999).

Masked titi groups inhabit home ranges that overlap with those of other groups. They are territorial and will aggressively chase, vocalize, and display towards other groups that they encounter.

A captive masked titi used pieces of straw to pry cockroaches out of crevices. This monkey also intentionally moved his sleeping box, presumably to obtain cockroaches that had accumulated underneath it (Hill, 1960; Nowak, 1999).

The diet of masked titis consists mostly of fruits but also includes vegetation, small invertebrates, bird eggs, and small vertebrates (Nowak, 1999). Titis will feed on fruit from 27 different plant species but the bulk of their diet comes from only a small number of species including Manilkara paraensis (Sapotaceae) (Kinzey and Becker, 1983).

Geophagy, consumption of soil, has been observed by Masked titis. There are record accounts of Masked titis eating soil from ant mounds and less commonly from the forest floor and decomposed tree trunks (Muller et al., 1997).

Masked titis occasionally feed with Geoffroy’s Tufted-eared Marmosets (Callithrix geoffroyi) (Rowe, 1996).

Masked titis are preyed on by large snakes, such as pit vipers and tree boas. They are also preyed on by cat species and by raptors (Muller 1997).

Masked titis are important in the ecosystems in which they live as prey for large predators. They may also disperse the seeds of the fruits they eat.

There are no negative effects of masked titis.

Masked titis are an important and charismatic component of a critically endangered habitat, making them potentially valuable to ecotourism.

Masked titis are listed as vulnerable by the IUCN and are on the CITES Appendix II list (Walker, 1999). At least 95% of their habitat has been cut down for lumber and charcoal production and to make way for agriculture and pasture. Their population continues to decline as human settlement and activity encroaches into the seriously imperiled Atlantic rainforests (Nowak, 1999).