Black-Fronted Titi, Callicebus nigrifrons
BLACK-FRONTED TITI
Callicebus nigrifrons
Geographic Distribution and Habitat
The black-fronted titi monkey is native to the Atlantic forest region of Brazil, including the surrounding areas of Cerrado savanna woodlands, living at elevations from near sea level up to about 3,280 feet (1000 m). They typically occupy a home range of around 50 acres (20 hectares). These monkeys are arboreal and spend most of their time in the forest canopy, though they can sometimes be observed foraging, playing, or traveling on the forest floor. Being quite an adaptable species, they can also be found in isolated forest fragments including in Serra da Cantareira State Park in São Paulo.
In the past, all titi monkeys were classified under the genus Callicebus. However, in 2016 a three-genus model was proposed and accepted. It consisted of the Cheracebus, Plecturocebus, and Callicebus genera. Since the black-fronted titi monkey is still considered to be in the Callicebus genus, no taxonomic changes have been made to distinguish the species since its original classification.
Size, Weight, and Lifespan
The black-fronted titi monkey can range from around 2.2-4.4 pounds (1-2 kilograms) with a head-to-body length of around 11-18 inches (27.94-45.72 centimeters). Unlike many primates, there is no sexual dimorphism, that is, males and females look alike. Their tails can often be even longer than their head-body length, ranging from 10-22 inches (26-56 centimeters).
Though there is not much concrete information regarding the wild lifespan of the black-fronted titi, other titi monkeys within the Callicebus genus are known to live anywhere from 12-20 years in the wild. Black-fronted titi monkeys have been documented living up to around 12 years in captivity. It is unlikely that they would live longer than this in the wild due to natural threats.
Appearance
An adorable mess of fluff and fur, black-fronted titi monkeys are defined by their black faces and plume of a coat that can range from gray to brown, to a peachy auburn. Most notably, their tail is long with a thick layer of dense fur that is usually more orange in color. Their eyes are dark brown, and their facial features are flat, including their nose. Oftentimes, the fur that frames their face sticks out and up about an inch, with their ears sometimes being detectable as two cute little semi-circles on either side.
Diet
Similar to other Callicebus monkeys, the main source of food for black-fronted titi monkeys is fruit, typically accounting for over 50% of their diet. Data from case studies indicated that these monkeys will heavily prioritize consuming fruit while fulfilling the rest of their caloric needs with lower-quality food items like leaves, invertebrates, flowers, seeds, and various animal matter. They have been observed eating over 50 different species of plants, including bamboo, nightshade, Lamiaceae, wild honeytree, and woody dioecious species.
Behavior and Lifestyle
The black-fronted titi is a diurnal primate, meaning they are active during the day and rest at night. They are an arboreal species and can be found anywhere from the lower to middle to upper canopy of the forest. They often exhibit a preference for staying near rivers. They travel through this zone by leaping from branch to branch or simply using all four limbs to climb. When they stop to feed, they will sit vertically on branches. They typically spend around 35% of their time feeding and traveling (around 24%), and dedicate the remainder of their time to resting, lounging, playing, and sleeping. Time spent resting and traveling doesn’t change much from season to season, but, during periods with lower temperatures, it is common for the monkeys to dedicate more time to feeding.
This species is extremely territorial, using various individual and group communication calls to defend their living zones, food resources, and families. Sleeping sites and behaviors are also carefully curated to ensure these monkeys feel as safe as possible from natural predators. They often climb the tallest trees in their area when it’s time to sleep, ascending higher than they do during the day and choosing branches with dense foliage to help keep them hidden while they rest. Family groups often avoid sleeping in the same location for more than one night in a row.
Black-fronted titis have been observed interweaving their tails with other monkeys within their families, a behavior that we assume helps strengthen bonds and social relationships. It’s like the titi version of holding hands, or hugging!
The black-fronted titi monkey is socially monogamous, a living arrangement between an adult male and female that does not necessarily describe the sexual interactions or reproduction between monogamous pairs; rather it refers to their living conditions. The arrangement consists of but is not limited to, sharing territory, obtaining food resources, and raising offspring. They may occasionally take other mates or they may take a new mate if one of the couple becomes injured, disappears, or dies. This differs from monogamy, which is a mating system in which a male and female mate exclusively with each other.
A black-fronted titi troop may include immediate offspring who are not yet old enough to be independent. At around three years old, both male and female offspring move on from their natal group to form their own pairs and families.
Interestingly enough, a recent case study published in 2023 found that three of the five black-fronted titi monkey groups they observed in the Caraça Private Natural Heritage Reserve in Minas Gerais, Brazil contained more than one adult male; there were three adult males in one of the groups, and two adult males in the other two groups. As mentioned, this is very uncommon for the species and suggests that there is still much to learn about these monkeys.
Black-fronted titis have formed incredibly intricate and impressive ways of communicating with each other through a variety of vocal calls. They utilize two alarm calls: one often referred to by scientists as their “A-call,” which is used to signal threats within the canopy, and the other called their “B-call,” used for terrestrial (land) predators, as well as communicating things other than threats. The monkeys will often combine these two calls in various ways, with specific sounds/combinations used to identify specific predator types and locations, including aerial threats. By stringing together previously established syllables to form long, identifiable calls, they are able to communicate definitive, declarative statements, much like humans — so impressive!
As mentioned before, the black-fronted titi is a very territorial species, and their vocal communication is the primary way in which this is expressed. They are known to not only make their calls individually, but also in duets or choruses that can last up to two hours, alternating between loud and quiet sounds. The loud calls are made with a high amplitude and a low frequency and can be heard from far distances. Gender makes no difference with these vocal behaviors, males and females make calls alike.
Black-fronted titis are socially monogamous. Females give birth to one infant a year, between the months of July and August, with gestational periods lasting around five months. Studies show that this birthing period is strategically planned around fruit availability, with births happening near the end of the low-fruit supply season and lactation starting just in time for increased fruit availability. Nursing is actually one of the few roles females hold in raising their young, with a majority of the parental care, nurturing, and play being led by the males.
Another “fun fact,” a study published in 2008 observed a rare case of infant adoption, the first known occurrence of this phenomenon within the Callicebus genus. During a long-term field study, one infant was seen moving into another family/group and was later seen nursing from the mother. 19 months later, this infant was still under the care of the adoptive family. Though female black-fronted titi monkeys usually give birth once a year, the mother who ended up caring for and nursing both her biological and adopted young ended up not giving birth the next year, suggesting that this adoption negatively affected her fertility and/or reproductive abilities.
Though unfortunate for the monkeys themselves, the black-fronted titi also contributes to their ecosystem by serving as a food source for many of the predators in the area, including raptors, harpy eagles, owls, hawks, falcons, snakes, pumas, jaguars, and even larger primates.
The black-fronted titi monkey is classified as Near Threatened by the International Union for Conservation of Nature (IUCN, 2015), appearing on the IUCN Red List of Threatened Species. There are a number of harmful human-based interactions that led to this classification, including residential and commercial development, agriculture and aquaculture, and biological resource use. Inhabiting the most urbanized and populated area of Brazil, these monkeys have dealt with vast amounts of habitat loss due to logging practices, and the development of cattle ranches, agriculture plots, and infrastructure. Furthermore, these human activities have led to more black-fronted titi deaths in the form of electrocution, road kills, and fatal injuries inflicted by domesticated dogs.
There was a major sylvatic yellow fever outbreak that occurred in Brazil between the years of 2016 and 2018, which affected many of the primates in the area. A study observed its impact on the black-fronted titi population, taking note that the population numbers were relatively stable between 2008 and 2016. However, by 2019 their numbers had decreased by 80%, suggesting that the yellow fever outbreak played a major role in this loss.
Another study observed the effects of mining noise within zones of black-fronted titi inhabitation. It was determined that these unnatural sounds may have limited the ability for these titi monkeys’ long-distance calls to be heard, possibly causing them to adjust their communication patterns in order to be better discerned. As we discussed earlier, black-fronted titi monkeys have very intricate and valuable forms of communication that help them ward off threats, so these mining noises could have seriously adverse consequences on the species.
Black-fronted titi monkeys are 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.
There are a number of protected areas where black-fronted titi monkeys live, including Serra da Cantareira State Park, the Serra do Mar reserve complex in São Paulo, and the Environmental Protection Area Sul in Nova Lima, Minas Gerais. Other than that, there are no published conservation efforts for the species.
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Written by Hannah Broadland, June 2024