Nycticebus bengalensis

The Bengal slow loris (Nycticebus bengalensis) or northern slow loris is a strepsirrhine primate and a species of slow loris native to the Indian subcontinent and Indochina. Its geographic range is larger than that of any other slow loris species. Considered a subspecies of the Sunda slow loris (N. coucang) until 2001, phylogenetic analysis suggests that the Bengal slow loris is most closely related to the Sunda slow loris. However, some individuals in both species have mitochondrial DNA sequences that resemble those of the other species, due to introgressive hybridization. It is the largest species of slow loris, measuring 26 to 38 cm (10 to 15 in) from head to tail and weighing between 1 and 2.1 kg (2.2 and 4.6 lb). Like other slow lorises, it has a wet nose (rhinarium), a round head, flat face, large eyes, small ears, a vestigial tail, and dense, woolly fur. The toxin it secretes from its brachial gland (a scent gland in its arm) differs chemically from that of other slow loris species and may be used to communicate information about sex, age, health, and social status. The Bengal slow loris is nocturnal and arboreal, occurring in both evergreen and deciduous forests. It prefers rainforests with dense canopies, and its presence in its native habitat indicates a healthy ecosystem. It is a seed disperser and pollinator, as well as a prey item for carnivores. Its diet primarily consists of fruit, but also includes insects, tree gum, snails, and small vertebrates. In winter, it relies on plant exudates, such as sap and tree gum. The species lives in small family groups, marks its territory with urine, and sleeps during the day by curling up in dense vegetation or in tree holes. It is a seasonal breeder, reproducing once every 12–18 months and usually giving birth to a single offspring. For the first three months, mothers carry their offspring, which reach sexual maturity at around 20 months. The Bengal slow loris can live up to 20 years. The species is listed as 'Vulnerable' on the IUCN Red List, and is threatened with extinction due to a growing demand in the exotic pet trade and traditional medicine. It is one of the most common animals sold in local animal markets. In traditional medicine, it is primarily used by wealthy to middle-class, urban women following childbirth, but also to treat stomach problems, broken bones, and sexually transmitted diseases. It is also hunted for food and suffers from habitat loss. Wild populations have declined severely, and it is locally extinct in several regions. It is found within many protected areas throughout its range, but this does not protect them from rampant poaching and illegal logging. Critical conservation issues for this species include enhancing protection measures, stricter enforcement of wildlife protection laws, and increased connectivity between fragmented protected areas. Nycticebus bengalensis, commonly known as the Bengal slow loris or northern slow loris, is a strepsirrhine primate in the slow loris genus, Nycticebus. Formerly considered a subspecies of the Sunda slow loris (N. coucang), it was recognized as a distinct species in 2001 by taxonomist and primatologist Colin Groves. It is difficult to distinguish from the other species in its genus. To help clarify species and subspecies boundaries, and to establish whether morphology-based classifications were consistent with evolutionary relationships, the phylogenetic relationships within the genus Nycticebus have been investigated using DNA sequences derived from the mitochondrial markers D loop and cytochrome b. Although most of the recognized lineages of Nycticebus (including N. pygmaeus, N. menagensis and N. javanicus) were shown to be genetically distinct—the analysis suggested that DNA sequences from some individuals of N. coucang and N. bengalensis apparently share a closer evolutionary relationship with each other than with members of their own species. The authors suggest that this result may be explained by introgressive hybridization, as the tested individuals of these two taxa originated from a region of sympatry in southern Thailand; the precise origin of one of the N. coucang individuals was not known. This hypothesis was corroborated by a 2007 study that compared the variations in mitochondrial DNA sequences between N. bengalensis and N. coucang, and suggested that there has been gene flow between the two species. The Bengal slow loris is the largest species of slow loris, weighing 1 to 2.1 kg (2.2 to 4.6 lb), and measuring between 26 and 38 cm (10 and 15 in) from head to tail. It has a skull length of more than 62 mm (2.4 in). It has dense, woolly, brown-gray fur on its back and white fur on its underside. It also has a clear dark stripe that runs up to the top of its head, but does not extend laterally towards the ears. Its forearm and hand are almost white. The limbs of the pelvis vary in color from brown to nearly white, and the feet are always pale. Moulting may cause seasonal variations in the color of the dorsal surface. Like other slow lorises, its tail is vestigial and it has a round head and short ears. It has a rhinarium (the moist, naked surface around the nostrils of the nose) and a broad, flat face with large eyes. Its eyes reflect a bright orange eye shine. On its front feet, the second digit is smaller than the rest; the big toe on its hind foot opposes the other toes, which enhances its gripping power. Its second toe on the hind foot has a curved 'toilet-claw' that the animal uses for scratching and grooming, while the other nails are straight. In addition to being smaller than the Bengal slow loris, the sympatric Sunda slow loris also differs in its coloring: it does not have the pale areas of the head, nape and shoulders, and its overall color is a tawny- or golden-brown. The pygmy slow loris (N. pygmaeus) is much smaller, with a skull length less than 55 mm (2.2 in). It also lacks the dark dorsal stripe of the Bengal slow loris, has dark brown fur, and longer ears. The Bengal slow loris has a small swelling on the ventral side of its elbow called the brachial gland, which secretes a pungent, clear oily toxin that the animal uses defensively by wiping it on its toothcomb. The oil has been analyzed using gas chromatography coupled to mass spectrometry, and it has been shown that almost half of the several dozen volatile or semi-volatile chemicals present do not occur in the closely related pygmy slow loris. The most predominant component was the phenolic compound m-cresol. The authors of the study suggest that the chemically complex oils may help the lorises communicate with each other, allowing them to transmit by scent information about sex, age, health and nutritional status, and dominance.