Geographic Distribution and Habitat
Ornate titis, sometimes called dusky titi monkeys, are Latin American primates that are endemic to the forests of eastern Colombia. Ornate titis are only found in northern regions and are separated from other closely related titis by at least 217 miles (350 km). Their range extends further north than that of other titi monkey species. Ornate titis can live in a variety of forest types but tend to prefer forests with lower canopies rather than tall trees.
When titi monkeys were first described, scientists classified them into two species with many subspecies. Recent studies have revealed that titis are, in fact, one of the most diverse primate groups in the world. Experts changed the titis’ taxonomic nomenclature (naming system) to reflect this diversity and elevated many titi subspecies, including the ornate titi, to an independent species level. The genus name of the ornate titi was changed from Callicebus to Plecturocebus. The new genus name comes from a combination of Greek words: “Plektos” means “twisted,” “Uro” means “tail,” and “kebos” means “long-tailed monkey.” The new name was inspired by the manner in which many titi species rest together on branches with their tails twisted in a braid.
Size, Weight, and Lifespan
These are small-sized primates, weighing about 2.6 pounds (1.17 kg) and with an average head-to-body length of between 11 and 14 inches (30–36 cm). Their fluffy tail is longer than their body, measuring between 15 and 17 inches (38–45 cm). Males and females are almost impossible to tell apart, which means they are sexually monomorphic (or you could say they are not sexually dimorphic).
Ornate titi monkeys can live for over 23 years in captivity.
Titis are slightly larger than house cats and can be identified by their roundish fluffy bodies, long, bushy tails, and long, hairless fingers. Ornate titis have bright reddish-orange fur over most of their chest and belly, with darker fur near their legs. Their backs are covered with grizzled, brownish-gray fur. They have a characteristic white stripe of fur across their forehead, mostly-white tails, and, in many cases, short white hairs under their eyes. But what sets them apart from similar-looking titi monkeys are the white tips of their ears and the pale gray-white color of their feet and hands.
Fruits form the major part of the ornate titis’ diet. They have also been observed feeding on insects like beetles. They often eat unripe fruits, which enables them to avoid competition with other primates that tend to prefer ripened fruits. Sometimes ornate titis will eat leaves and flowers. This flexibility in their diet gives them a survival advantage over other primates in their habitat.
Behavior and Lifestyle
Ornate titis are most active in the mornings (they are diurnal). They spend the cooler part of the day foraging for food and resting in the afternoons when it gets too hot for intense activity.
They spend most of their time in the tree canopy (they are arboreal) but tend to stay in lower canopy areas and even sometimes descend to the ground to eat insects and fallen fruits. This ability to feed in the different layers of the forest gives them an evolutionary advantage in adapting to their decreasing forest home range.
Ornate titis are rather playful, even as adults. Captive individuals take part in “play wrestling,” run around with juveniles, and readily interact with each other. In the wild, siblings play with each other and interact with adults when they are not foraging for food.
Allogrooming, or individuals grooming one another, is most often observed between mated pairs or family members. This grooming behavior usually occurs during afternoon rest periods and serves as a way for group members to rid their fur of insects and pests. It also reinforces social bonds.
The physical need to be in close contact with each other is especially notable in their behavior of “tail-twining.” When ornate titis rest, they often stay close together and wrap their tails together to form a braid. This behavior helps the monkeys anchor securely to the branch while they fall asleep, but mainly it is an act of social bonding and trust—just as you would hold hands with a loved one.
In reaction to seeing predators and researchers, wild ornate titis perform a behavior called “swaying,” where they grip the tree branch firmly with their hands and legs and sway only their bodies from side to side. It almost appears as if the monkeys are bobbing and weaving, and it is likely a behavior that prepares the titis to escape quickly—like a warm-up exercise! Swaying also lets predators know that the monkeys are aware of the danger, which would make ambushing the monkeys difficult.
Ornate titis will twist their tails together when resting in trees to increase their social bonds with each other—just like you would hold hands with a loved one.
They use complex songs and resonating notes to communicate with each other, especially in the morning hours.
Ornate titis can travel and feed at different levels of the forest, which enables them to take advantage of all the forest resources and potentially resist some perils of deforestation.
Ornate titis spend most of their time resting as they digest their food and conserve their energy. Family members are close-knit and are often seen resting together with their tails intertwined. The next big activity for the day is finding and consuming food within their home range. Male ornate titis carry the baby monkeys most of the time and usually hand off the infant to the mother only during feeding times.
Ornate titi monkeys live in small groups with a mated pair of adults and their offspring. The pair will defend their territory from other mated pairs and families. This is one way they ensure that they have enough food for their young. Both adult males and females will first warn of trespassing titis with vocal calls. If rival monkeys refuse to back off, a physical fight will break out between the territory owners and the rivals. However, in the wild, physical fighting is considered a last resort because it takes a lot of energy and can harm both the trespassing monkey and the territory holder. So actual fights rarely occur. In reality, many family units will tolerate each other’s presence. If there is a lot of food available, as there may be during the fruiting season, neighboring families will even share resources.
Studies on wild titi monkeys are rare because of their arboreal lifestyle, which makes long observations through the leaves and trees difficult. In captivity, the main challenge is that closely related titi species appear similar. In many cases, monkeys in zoos do not have reliable data on where they were captured, which can make identifying individuals difficult when different species look alike. So research on captive titis is not reliable for ornate titis specifically but can provide insights on the titi monkey group in general. We should also be mindful that captive individuals may behave differently from wild ones, and captive studies are more accurate for biological information (such as body size or shapes, digestion rates, and birth rates) than behavioral information (such as territorial aggression, grooming, and playing).
Ornate titis use their sense of smell to gain information about their environment. When these monkeys encounter a new item in their environment, like a new fruit or a new family member, one of the first things they do is gently approach and sniff. With their sense of smell, they can determine if a food item is safe to eat. They can also detect hormones from other ornate titi monkeys. Both males and females might sniff each other under the tails to smell the gland secretions and determine if their partner is ready to mate (which means all hormones will be at the right concentration levels). Sometimes adult males will rub glands in their chests against branches. Researchers think that males use their chest glands to spread a scent on these branches to mark territory. This gland secretion will have information about that titi’s identity—for example, how old or healthy he is.
Allogrooming (grooming one another) uses the sense of touch to communicate affection, and this act reinforces social bonds and trust between members. We can relate to this idea by thinking about how we would not allow someone we did not trust to comb our hair. So, the act of allogrooming is usually done between family members.
Ornate titis make a complex series of sounds similar to bird songs. These songs include squeaks, chirrups, and moans. The loudest of these is referred to as “resonating notes.” In the wild, resonating notes are commonly heard at the start of the titis’ day in the form of a “morning song.” Resonating notes are mostly used to communicate with rival families. The more excited the titis get in their arguments, the more song-like phrases they add to their resonating notes! This vocal display could be a way of letting other ornate titis know that the monkeys survived the night and are still around to defend their territory that day.
The most common vocalization among wild ornate titis is “chirrups,” which seems to have many meanings and is associated with escaping predators, friendly encounters with other family members, and attacking enemies. Most likely, it is a sound of excitement. Ornate titis also use squeaks, whistles, trills, and screams to communicate with each other.
Adult male and female ornate titis form mating pairs, and most titis stay in these pairs for their whole lives. A female may leave a mate to join another adult male, or another adult male may lure away an already mated female, but this is not common.
Males initiate mating by sniffing the female’s reproductive parts (under the tail). Once conception is achieved, ornate titis have a gestation period (the time the female is pregnant) of around 4 months, and they almost always give birth to one offspring at a time (twins are rare).
A family consists of a mated male and female and their young offspring. Ornate titi parents share their childcare duties. Mothers nurse the offspring, and the father carries the infant while the family moves and forages for food. Infants start to gain independence at around 3 months of age, when they will venture off their father’s back and explore their surroundings more. By the time they are 6 months old, young ornate titis will feed and move around on their own.
Subadult ornate titis remain with the family even after the next offspring is born, but they will eventually leave their natal troop to form their own family. Adult females only mate with unfamiliar males. This ensures that mating does not occur between closely related individuals, which reduces the chances of inbreeding and related resulting health problems.
Ornate titis use different parts of the forest, which connect multiple species through a complex food chain. They travel between the upper and lower canopy regions, eating fruits that other primates may not access. When ornate titis eat fruits, they spit out the hard seed. This can help spread seeds and regenerate important plant species. These primates also descend to the ground and prey on insects and other invertebrates. This diversity in their diet gives ornate titis the advantage of surviving a reduction in available fruit due to deforestation. One study even found that the size of forest fragmentation did not negatively affect ornate titi population density (the number of titis per area of forest). So while other primate species are more sensitive and may not survive habitat loss, ornate titis may be one of the last primates to be found in these fragmented forests. However, if habitat destruction continues, even the adaptive ornate titi will not be able to find enough food and shelter to survive.
The main predators of titi monkeys are raptors, such as hawk eagles and crested eagles. Observations of ornate titis in the wild have suggested that they rarely fall prey to these birds and do not behave like they are overly fearful of predators. So the ecological role of ornate titis is as a consumer in the ecosystem and not as a prey source for other animals.
The International Union for Conservation of Nature lists the ornate titi as Vulnerable (IUCN, 2015), appearing on the IUCN Red List of Threatened Species.
Ornate titis monkeys are only found in a small region of Colombia, and so their historic natural habitat was limited even before human development. Now, agriculture, urbanization, mining for resources (mostly oil), and civil unrest are the main reasons for the severe forest fragmentation in this region. Agriculture and oil exploration not only result in deforestation, but they also destroy the soil and pollute water sources with chemicals. This has a cascading effect on the surrounding natural areas and all the wildlife in the region.
Colombia has experienced unstable political systems with dictatorships, military coups, and guerilla warfare. These political and violent periods lead to poverty, and wildlife conservation is not a priority. Forests are seen as land that can be used for farms, trees that can provide firewood and lumber, or shelter for armed combatants. Many wild animals are hunted during such times just to feed families. These political situations have a devastating affect on the people and environment of the country for generations.
Although ornate titis can tolerate habitat loss better than other primate species in the region, their population is currently declining due to excessive changes to their native habitat. One study estimated an average of 0.8 individuals per acre (192 individuals per square km).
The pet trade and hunting are not major reasons for their population decline, so there are fewer regulations regarding the illegal capture of these species.
The ornate 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. An Appendix II listing means that right now, ornate titis are not threatened with extinction, but their declining population may be affected if trade is not monitored closely. Ornate titis may not be in large demand for the pet trade compared to other primate species, but constant monitoring of how many species are captured or traded is vital to ensure the continued survival of the species in the wild.
The La Macarena and Tinigua National Parks in Colombia provide protected spaces for ornate titis, and the highest population of these primates is found around these two areas. Historically, Colombia has faced challenges with political instability and violence, making research in some of these wild spaces impossible. And so conservation laws and practices are difficult to enforce across the nation.
- Byrne, Haze. Thesis:Evolutionary history and taxonomy of the titi monkeys (callicebinae). University of Salford (United Kingdom), 2017.
- Carretero-Pinzon, Xyomara, and Thomas R. Defler. “Callicebus ornatus, an endemic colombian species: demography, behavior and conservation.” Ruiz-García, M. & J. Shostell. Phylogeny, molecular population genetics, evolutionary biology and conservation of the Neotropical primates. Nova Science Publisher Inc (2016).
- Carretero, X., Guzmàn-Caro, D., Palacios, E. & Stevenson, P.R. 2020. Plecturocebus ornatus. The IUCN Red List of Threatened Species 2020: e.T39928A17974735. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39928A17974735.en. Accessed on 24 May 2023.
- Castillo Ayala, Claudia I. Thesis: “Conservation planning for non-human primates in Colombia (South America).” (2016).
- GBIF, Global Biodiversity Information Facility. Callicebus ornatus (Gray, 1866) in ITIS, Alexander, S., Hodson, A., Mitchell, D., Nicolson, D., Orrell, T., & Perez-Gelabert, D. (2022). The Integrated Taxonomic Information System. In O. Bánki, Y. Roskov, M. Döring, G. Ower, L. Vandepitte, D. Hobern, D. Remsen, P. Schalk, R. E. DeWalt, M. Keping, J. Miller, T. Orrell, R. Aalbu, J. Abbott, R. Adlard, E. M. Adriaenssens, C. Aedo, E. Aescht, N. Akkari, et al., Catalogue of Life Checklist (Version 2022-12-21). ITIS. https://doi.org/10.48580/dfqz-4ky. Accessed May 24, 2023.
- Hernández-Camacho, Jorge I. “Conservation priorities for Colombian primates.” Primate conservation 19 (2003): 10-18.
- Moynihan, M., 1966. Communication in the Titi monkey, Callicebus. Journal of Zoology 150, 77–127.. https://doi.org/10.1111/j.1469-7998.1966.tb02999.x
- Souza-Alves, João Pedro, Italo Mourthe, Renato R. Hilário, Júlio César Bicca-Marques, Jennifer Rehg, Carla C. Gestich, Adriana C. Acero-Murcia et al. “Terrestrial behavior in titi monkeys (Callicebus, Cheracebus, and Plecturocebus): Potential correlates, patterns, and differences between genera.” International Journal of Primatology 40 (2019): 553-572.
- Valeggia, C. R., S. P. Mendoza, E. Fernandez‐Duque, W. A. Mason, and B. Lasley. “Reproductive biology of female titi monkeys (Callicebus moloch) in captivity.” American Journal of Primatology: Official Journal of the American Society of Primatologists 47, no. 3 (1999): 183-195.
- Van Roosmalen, Marc GM, Tomas van Roosmalen, and Russell A. Mittermeier. “A taxonomic review of the titi monkeys, genus Callicebus Thomas, 1903, with the description of two new species, Callicebus bernhardi and Callicebus stephennashi, from Brazilian Amazonia.” Neotropical Primates 10, no. sSuppl (2002).
- Wagner, Castro, F., & Stevenson, P. R. (2009). Habitat Characterization and Population Status of the Dusky Titi (Callicebus ornatus) in Fragmented Forests, Meta, Colombia. Neotropical Primates, 16(1), 18–24.
Written by Acima Cherian, May 2023