Белоухий тити: описание и особенности вида.

Species of New World monkey

The white eared titi monkey (Plecturocebus donacophilus) also known as the Bolivian titi or Bolivian gray titi, is a species of titi monkey, a type of New World monkey, from eastern Bolivia and an area of western Brazil. The species has a range that extends east from the Manique River in Beni Department, Bolivia to southern Rondônia in Brazil. The southern end of its range includes forests around the city of Santa Cruz de la Sierra. It is a medium sized monkey with a grey back, orange underside and distinctive white ear tufts. It has an omnivorous diet, eating fruits, other plant materials and invertebrates. It is predated upon primarily by raptors, though felids and other monkey species have been known to attack the species. It is a monogamous species and lives in small groups of two to seven members consisting of the pair and their offspring. The family group has a home range of and the adults have a complex vocal repertoire to maintain their territory. It is also known for its characteristic twining of tails when groups are sitting together. White eared titis can live for more than 25 years in captivity. The white eared titi population has a declining trend. The decline is believed to be mainly caused by human induced habitat loss and degradation. Despite this, the International Union for Conservation of Nature (IUCN) classified the species as being of least concern in 2008 as it has shown adaptability to habitat disturbance and is found over a wide range.

The white eared titi belongs to the New World monkey family Pitheciidae, which contains the titis, saki monkeys (Pithecia), bearded sakis (Chiropotes), and uakaris (Cacajao). It is a member of the subfamily Callicebinae. It was first described as Callicebus donacophilus in 1836, but was reassessed based on molecular evidence and recombined as a species within the genus Plecturocebus. Within the new genus Plecturocebus, the white eared titi is part of the P. donacophilus group with the Rio Beni titi (P. modestus), Rio Mayo titi (P. oenanthe), Olalla brothers' titi (P. olallae), white coated titi (P. pallescens), and Urubamba brown titi, (P. urubambensis). but they are treated as separate species in the latest edition of Mammal Species of the World. Body weight ranges from around , with the female generally a little lighter. The canine teeth are relatively short when compared with other New World monkeys. In captivity, the white eared titi has been known to live for over 25 years.

The white eared titi is cryptic, diurnal and known to live in small family groups. It is a monogamous species that is thought to mate for life and lives in groups that usually consist of two to seven members; an adult pair and up to five young. Multi male groups have also been recorded. Offspring are carried by the male, and are always with them, except when feeding. There is a strong bond between the adult mating pair, they stay close and carry out activities together. Either member of the pair may follow the other and leadership changes through the day. Evidence of the strength of the pair bond is shown by grooming, huddling together with their tails twined, nuzzling, and gentle grasping. When not close together, the pair show a significant amount of distress and agitation. Titi monkeys are well known for their vocal communication, and have a complex repertoire of calls. The calls can be divided into two categories: high pitched quiet calls and low pitched loud calls. Vocalisations are often combined and repeated to form sequences that are used to indicate distress, conflict, play, bonding, disturbance, and to strengthen territory. The loud low pitched calls are mostly used in long distance group calling. Their function is to ensure adequate spacing between the home ranges of different family groups. These vocalisations are known as duets, and generally involve the male and female. If a neighbouring group is within earshot of these calls they will respond with their own duetting. During normal movement through its environment it is quadrupedal and mostly walks, clambers and leaps, but it can also bound and climb. When travelling on the ground it is said to use a "bounding movement"

There is relatively little known about the ecology of the white eared titi or even titi monkeys in general, Food availability may influence activity times; if there is an abundance of food in the warmer months when plants are fruiting titi monkeys may start earlier, or if there is a lack of food, titi monkeys may remain at the feeding tree into the evening. Though there is little published research on the diet of the white eared titi, titi monkeys in general are omnivores that eat fruit, leaves, insects, and seeds. They mostly eat leaves, especially protein rich young leaves and leaf buds, so a significant period of the day is spent resting to digest the cellulose. During the dry season there is an increased feeding time on leaves, and during lactation it is thought insect consumption increases to augment the protein content of the diet. The titi monkey may travel between during the day, and can maintain a home range of During the dry season there is less fruit available and therefore less need to travel large distances, so the day range may only be a third of the usual distance. and will generally try to avoid other primates. It is found in areas with dense vegetation, often choosing to inhabit the thickest parts of the forest. and some groups can thrive in disturbed habitats near human activities. Forest corridors to connect fragmented forests have been proposed as an effective means to help ensure the survival of the titi monkey. The white eared titi is found in the Beni Biological Station Biosphere Reserve and the Amboro National Park in Bolivia and benefits from the protection these reserves provide.