Bolivian titi monkeys, Callicebus donacophilus, are primarily found in eastern Bolivia in the upper basins of the Mamore River and the Rio Grande. They may also be found in the extreme southwestern parts of the Brazilian states of Mato Grasso and Rondônia. (Ferrari, et al., 2000; Hershkovitz, 1990)
Bolivian titi monkeys inhabit riparian zones and gallery forests near swampy grasslands and other open areas. (Ferrari, et al., 2000)
Bolivian titis are small, New World monkeys , averaging about 320 mm in length. Males are only slightly larger than females, weighing on average 991 g while females weigh 909 g. Titis have long tails that are not prehensile. They have very little prognathism and long skulls. Titi monkeys have long hind limbs with an intermembral index of 75.
The chest and belly of Bolivian titi monkeys is completely orange to brown-orange while the dorsal side and extremities range from grey to orange agouti in color. The tail may include black or grey coloring, and they have white tufts on their ears.
The dental formula of Bolivian titis, as with other titi monkeys, is 126.96.36.199/188.8.131.52. Compared to other platyrrhines, the canines of titi monkeys are relatively short and their molars are fairly simple.
Bolivian titi monkeys can be distinguished from closly related speices including Callicebus olallae, Callicebus brunneus, and Callicebus modestus by their well-developed malar stripe and lack of distinct sideburns. (Fleagle, 1999; Hershkovitz, 1990; van Roosmalen, et al., 2002)
Like all titi monkeys, Bolivian titis are monogamous. A strong bond is formed between male and female partners, which generally mate for life. They remain in close proximity to one another for almost all of their activities and often rest together with hands clasped and tails interwoven in a characteristic manner known as “twining.” They also have been observed grasping feet, nuzzling, and lip-smacking. When apart, they display physical signs of anxiety and distress. Titi monkeys also exhibit “jealous” behavior when approached by a stranger, especially the male, who mounts and tightly grasps his mate in the presence of another individual to prevent “extramarital” relations. (Anzenberger, et al., 1986; Mendoza, et al., 2002; Valeggia, et al., 1999)
In captivity, Bolivian titi monkeys breed throughout the year. In the wild, a breeding season is predicted, perhaps in the spring preceding the rainy season in Bolivia. In captivity, female titi monkeys give birth approximately one year after finding a mate. After a gestation period of about 18 weeks, females give birth to a single offspring, though twins are uncommon. Although female Bolivian titi monkeys reach sexual maturity at 2 years of age, the mean age of first birth is 4 years. (Gron, 2007; Valeggia, et al., 1999)
Male Bolivian titi monkeys play a dominant role in the care of their young. Although females nurse their offspring, males are the principal carriers and protectors of their young. During the first week of life, mother Bolivian titi monkeys carry their infants only 20% of the time, and after the first month, maternal contact is scarce. Infants experience more stress and elevated heart rates when separated from their father than from their mother, with few exceptions. Bollivian titi monkeys experience a stronger bond with their mate than with their offspring. (Mendoza and Mason, 1986)
The oldest Bolivian titi in captivity reached 24.8 years of age. Little information is available regarding the lifespan of this species in the wild. Other members of the genus Callicebus, such as Callicebus moloch, live an average of 25 years. (Gron, 2007; de Magalhaes, et al., 2009)
Bolivian titi monkeys may live in family groups of 2 to 7 members. Although males exhibit some degree of leadership in these groups, no dominance hierarchy has been observed between sexes or among individuals. Adult titi pairs remain close to each other throughout life and coordinate their activities so as to not spend a great amount of time physically apart. Members of a mated pair often entwine their tails during sleep. Bolivian titis generally sleep close to their group members in the vines of small branches.
Like most New World Monkeys, Bolivian titis are diurnal, with daily activity lasting an average of 11.5 hours. Titis wake early in the morning around sunrise and remain active until sunset. They generally divide the day into two main feeding times with a rest during midday.
Bolivian titi monkeys are arboreal and quadrupedal, primarily traveling through the lower levels of the forest. They are rarely seen on the ground. Locomotion generally consists of short leaps, for which their long hind limbs are well-adapted, and they also walk and climb. Because their tails are not prehensile, the tail does not come into contact with the surface on which they are walking.
Titi monkeys have small home ranges, and they do not exhibit considerable curiosity. They are wary and hesitant to approach new situations. They are, however, territorial and utilize a variety of vocalizations to define and reinforce their territory. (Anzenberger, et al., 1986; Kinzey, 1978; Kinzey, 1981; Valeggia, et al., 1999; Youlatos, 1999)
Titi monkeys, including Bolivian titis, utilize a variety of vocalizations in order to communicate. These vocalizations are complex and numerous, though they are generally classified into two groups: the higher pitched squeaks, trills, chirps, and grunts; and the lower pitched chirrups, moans, pants, honks, bellows, pumps, and screams. Higher pitched sounds tend to be employed when they are agitated or encounter violence. Lower pitched, louder sounds are often used in intra-group signaling as well as contacting other social groups over a long range. Certain chirrup sounds are believed to reveal information about the age and sex of the calling monkey and can be used to locate group members. Moans can be heard during copulation and greeting.
Titis perform a characteristic bout of vocalizations at the outer boundary of their relatively small range to define and reinforce the boundaries of their home range. This generally occurs in the morning soon after awakening. A male emits loud calls, moans, grunts, and other vocalizations in order to establish the boundaries. If a neighboring group draws near, the groups participate in what is known as "duetting", with both groups calling. As the groups draw together, the intensity of this duetting increases and both males and females participate. If two groups directly confront each other, more physical communication is exhibited included tail-lashing, piloerection, chasing, and further calling.
Titi monkeys also use physical communication, including grooming and tail entwining. Male and female mates show a strong preference for grooming and entwining with each other rather than with other members of their group. (Moynihan, 1966; Müller and Anzenberger, 2002; Robinson, 1979)
Bolivian titi monkeys are primarily frugivorous, and it is estimated that their diet consists of over 70% fruit. They also eat leaves, seeds, and insects. Much of the day is spent resting in order to digest their mostly herbivorous diet. (Wright, 1989)
Many species of raptors prey on titi monkeys, like Bolivian titi monkeys, including Guianan crested eagles and ornate hawk eagles. Other predators include felids such as jaguars as well as various arboreal snakes. Predation on infants by tufted capuchins has also been observed. Bolivian titis are have a cryptic coloration, helping them to blend in with their surroundings and avoid predation. (Gron, 2007)
Titi monkeys, including Bolivian titis, can coexist with many other New World monkeys including marmosets, tamarins, squirrel monkeys, capuchins, owl monkeys, howler monkeys, woolly monkeys, and spider monkeys. However, some of these larger species often chase titi monkeys away from fruit trees and other sources of food. Because titi monkeys prefer to remain isolated within their social group, they attempt to avoid contact with other primates.
Because they are frugivores, Bolivian titi monkeys may play a small role in seed dispersal.
The main parasites found in neotropical primates, including Bolivian titi monkeys, are trypanosomes (Trypanosoma cruzi, Trypanosoma rangeli, Trypanosoma minasense, and Trypanosoma devei), which are a prevalent cause of infection. (Gron, 2007; Wright, 1989; Ziccardi, et al., 2000)
Bolivian titi monkeys may play a part in drawing tourists to forested areas of Bolivia.
There are no known adverse effects of Bolivian titi monkeys on humans.
Although populations are declining, Bolivian titi monkeys are listed by the IUCN as a species of least concern. They have a relatively wide range and a slowly declining population. Bolivian titi monkeys have proven fairly adaptable, and they have a low number of natural predators. Their main threat is attributed to habitat loss due to agriculture. Bolivian titi monkeys are one of three primate species that survive within and around the borders of cities and rural human establishments in this region. (Veiga, et al., 2008)
Nicholas Venturelli (author), Yale University, Eric Sargis (editor), Yale University, Gail McCormick (editor), Animal Diversity Web Staff.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
Referring to an animal that lives in trees; tree-climbing.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
an animal that mainly eats fruit
An animal that eats mainly plants or parts of plants.
parental care is carried out by males
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats all kinds of things, including plants and animals
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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