Geographic Distribution and Habitat
The collared titi (Cheracebus torquatus), also known as the yellow-handed titi or the widow monkey, occupies the lush rainforests of the Amazon and is generally found north of Rio Solimões and south of Rio Negro, although their exact range is unclear, in part due to unclear distinctions between related species. They are believed to be endemic to Brazil, but it’s possible that they also live in southeastern Colombia, between Rio Apaporis and Rio Vaupés. They prefer mature forests with open canopies and tall trees that grow in nutrient-deficient, well-drained soils. Titis as a whole have been found living in highly disturbed habitats, although it is not known how tolerant collared titis may be to disturbed habitat.
TAXONOMY IN TRANSITION
In recent years, the taxonomy of the titi monkeys has been revised several times. Prior to 2016, collared titis, like all titis, were considered part of the Callicebus genus, which was subsequently broken down into three new genera: Cheracebus, Plecturocebus, and Callicebus. This decision was made to account for the large amount of diversity found among titi monkeys. The Cheracebus genus is the most ancient of the titi genera, with this branch diverting from other titis approximately 11–13 million years ago.
There is ongoing debate as to how many species comprise the Cheracebus genus, with six species often being cited: Lucifer titi (C. lucifer), black titi (C. lugens), Colombian black-handed titi (C. medemi), Rio Purus titi (C. purinus), red-headed titi (C. regulus), and, of course, collared titi. One 2020 study based on museum specimens suggests that Rio Purus titis are a synonym for collared titis, and redefines the distinction between black titis and collared titis based on geography. Another study from the same year proposed that black titis are the closest living relatives of collared titis, while Rio Purus titis are not as closely related. It is clear that ongoing research is needed to clarify the relationships within Cheracebus.
Size, Weight, and Lifespan
Large for titis, collared titis range in weight from 39 to 53 oz (1.1–1.5 kg) and in length from 9 to 14 in (23–36 cm). Specific lifespan data is not available, although titis generally are believed to live into their early 20s in the wild and may reach their late 20s in captivity. Interestingly, some studies show that male titi monkeys tend to outlive females by 10–20%, perhaps as an evolutionary response to their highly involved roles as parents.
Collared titis are small monkeys, with long, glossy hair that is black on the underside and lightens to a rusty brown on their backs. Their hands are a light tan or yellow color. Their faces are gray, and, true to their name, they sport a distinct white collar of hair on their necks. Their nickname “widow monkey” comes from their pale face, white collar, and “gloved” hands contrasting with their otherwise dark body, giving them the appearance of a widow in mourning. In some parts of their range, rare individuals have reduced melanin pigment, giving them a cream-colored pelage instead of the usual black-brown. Their tails are long, furry, and not prehensile. There is no apparent sexual dimorphism among collared titis.
Like other titis, collared titis enjoy a diet composed mainly of fruit pulp, leaves, seeds, and small invertebrates. Their diet likely varies slightly throughout the year and as their life stage changes. For example, some titi monkeys have been known to eat a larger proportion of leaves in the dry season, and females tend to eat more invertebrates while lactating, most likely because of their increased protein needs.
One study of the closely related black titi found that they consume 51 species of plants, although over half their diet was composed of just five species, including a species of bamboo, wild honeytree, and wetland nightshade. Because they live in a similar geographic area, collared titis likely eat many of the same plant species.
What Does It Mean?
The level of variation of life in an ecosystem, a biome, or the entire planet. Biodiversity is a measure of the health and function of an ecosystem.
Beneath the emergent layer, the canopy layer is the primary layer of the forest and forms a roof over the two remaining layers (the understory and forest floor). Many animals live in this maze of leaves and branches, where food is abundant.
The permanent cutting, clearing, and removal of trees to convert forest land for other use, such as pasture, cropland, or plantations.
A temporary change in environmental conditions that causes a pronounced change in an ecosystem.
Active during daylight hours.
Native or restricted to a certain area or country.
The time of pregnancy from conception until birth.
An animal that feeds on plants.
Having only one sexual partner.
Nonprehensile or Non-prehensile:
Incapable of grasping or gripping (opposite of prehensile: capable of grasping).
Using four limbs to move about. This word comes from the Latin meaning “four feet.”
When males and females have different characteristics (size, color, etc.) other than their reproductive organs.
A branch of science that encompasses the description, identification, nomenclature, and classification of organisms.
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Behavior and Lifestyle
Collared titis are arboreal and diurnal, waking up and going to sleep with the sun. They are quadrupedal, usually found walking or climbing, and using short leaps to move between gaps in trees. Their tail is held raised, never brushing against the ground or branch supports while they walk. They tend to occupy lower levels of the forest, favoring the understory and brush layers, although they also regularly climb into the lower canopy. They usually rest perched on top of narrow horizontal branches, and their sleeping sites are usually vine tangles on small branches that are at least 49 ft (15 m) above the ground. These sleeping sites may be reused several nights in a row. While sleeping, groupmates stay huddled close together.
Daily Life and Group Dynamics
Collared titis live in small, territorial groups composed of a bonded pair and their offspring. Groups are led by an adult male, who leads group movements and searches for foraging trees. Their home ranges are relatively small, at 4–74 acres (1.5–30 ha), and they typically range just 0.3–1 mile (0.5–1.5 km) on a normal day, although this can vary depending on weather and other circumstances. Their daily range is usually much shorter during the dry season to conserve energy, as fruit is less abundant.
They typically feed in the early morning, and spend the middle of the day resting. Their mostly vegetarian diet allows them to have plenty of time to rest, and even when they do consume prey, they rarely go to seek it out, instead preferring to sit still and wait for a moth or spider to come into view. After their mid-day rest, they have a shorter feeding period that is usually focused on leaves, then search for a tree in which to spend the night. In warmer months, titis rise early, sometimes before dawn, and in colder months they sleep longer, sometimes not rising until four hours after dawn.
Titis are known to intertwine their tails with a groupmates’ when sitting together, an affectionate behavior known as “tail twinning.”
Titis communicate through vocalizations, olfactory cues, and visual signals. Their vocalizations are extremely diverse, using a wide array of sounds to communicate with groupmates. Titis are sometimes known to “duet” with each other, either between an adult male and adult female, an adult male and his daughter, or an adult female and her son.
Reproduction and Family
Reproduction is unfortunately not well-studied in collared titis. They are considered monogamous, living and mating with one individual to whom they are pair bonded. Offspring stay with their parents until about three years of age. A related species, the dusky titi (Plecturocebus moloch), is known to give birth from December to April, after a gestation time of five to six months. Mothers nurse their young for 12 to 16 weeks, and can give birth to a new offspring after one year. Titi males contribute heavily to offspring care, carrying the infant whenever he or she is not actively nursing. Females contribute little to parenting besides nursing.
It’s possible that collared titis may live sympatrically with black titis, although this is not known for certain. Titis of the Cheracebus genus have been noted to be outcompeted by other titi species with whom they share habitat, and forced into areas with poorer vegetation. No predation data is available for collared titis, although a related species, masked titis (Callicebus personatus) are known to be preyed upon by birds of prey, large cats, and snakes. Collared titis most likely contribute to seed dispersal due to their consumption of fruit.
Conservation Status and Threats
The International Union for Conservation of Nature lists collared titis as Least Concern (IUCN, 2018) because of their relatively large range and lack of an apparent population decline that would warrant them being considered threatened. That said, data on the population size is extremely limited, with no information available as to recent population trends or population size estimations. This is due, in part, to the confusion around taxonomy, as there is no clear consensus on how many species make up the Cheracebus genus.
Collared titis are hunted by local people, but the hunting does not appear to significantly affect population size. Their greatest threat is habitat loss, mainly due to deforestation for cattle ranching. Deforestation in the Amazon rainforest is extremely concerning because it is the most biodiverse forest on earth. In the last 50 years, 17% of the Amazon rainforest has been lost to deforestation, threatening collared titis and the millions of other species of animals and plants that live there.
Collared titi habitat is partially protected by Jaú National Park. It is also listed on Appendix II of the Convention on International Trade in Endangered Species (CITES).
- Byrne, H., A.B. Rylands, S.D. Nash, J.P. Boubli. 2020. On the Taxonomic History and True Identity of the Collared Titi, Cheracebus torquatus (Hoffmannsegg, 1807) (Platyrrhini, Callicebinae). Prim Cons 34.
- Carneiro, J., I. Sampaio, T. Lima, et al. 2020. Phylogenetic relationships in the genus Cheracebus (Callicebinae, Pitheciidae). Am J Primatol 2(9). https://doi.org/10.1002/ajp.23167
- dos Santos, G.P., C. Galvão, R.J. Young. 2012. The diet of wild black-fronted titi monkeys Callicebus nigrifrons during a bamboo masting year. Primates 53(3):265-72. doi: https://doi.org/10.1007/s10329-012-0295-5
Written by K. Clare Quinlan, October 2020