Binturong

The binturong (Arctictis binturong), also known as the bearcat, is a viverrid native to South and Southeast Asia. It is uncommon in much of its range, and has been assessed as Vulnerable on the IUCN Red List because of a declining population. It is estimated to have declined at least 30% since the mid-1980s. The binturong is the only species in the genus Arctictis.

Etymology
"Binturong" is its common name in Borneo, and is related to the Western Malayo-Polynesian root "ma-tuRun". In Riau, it is called "benturong" and "tenturun".

The scientific name Arctictis means 'bear-weasel', from the Greek arkt- "bear" + iktis "weasel".

Taxonomy
Viverra binturong was the scientific name proposed by Thomas Stamford Raffles in 1822 for a specimen from Malacca. The generic name Arctictis was proposed by Coenraad Jacob Temminck in 1824. Arctictis is a monotypic taxon; its morphology is similar to that of members of the genera Paradoxurus and Paguma.

In the 19th and 20th centuries, the following zoological specimens were described:
 * Paradoxurus albifrons proposed by Frédéric Cuvier in 1822 was based on a drawing of a binturong from Bhutan prepared by Alfred Duvaucel.
 * Arctictis penicillata by Temminck in 1835 were specimens from Sumatra and Java.
 * Arctictis whitei proposed by Joel Asaph Allen in 1910 were skins of two female binturongs collected in Palawan Island in the Philippines.
 * Arctictis pageli proposed by Ernst Schwarz in 1911 was a skin and skull of a female collected in northern Borneo.
 * Arctictis gairdneri proposed by Oldfield Thomas in 1916 was a skull of a male binturong collected in southwestern Thailand.
 * Arctictis niasensis proposed by Marcus Ward Lyon Jr. in 1916 was a binturong skin from Nias Island.
 * A. b. kerkhoveni by Henri Jacob Victor Sody in 1936 was based on specimens from Bangka Island.
 * A. b. menglaensis by Wang and Li in 1987 was based on specimens from the Yunnan Province in China.

Nine subspecies have been recognized forming two clades. The northern clade in mainland Asia is separated from the Sundaic clade by the Isthmus of Kra.

Characteristics


The binturong is long and heavy, with short, stout legs. It has a thick coat of coarse black hair. The bushy and prehensile tail is thick at the root, gradually tapering, and curls inwards at the tip. The muzzle is short and pointed, somewhat turned up at the nose, and is covered with bristly hairs, brown at the points, which lengthen as they diverge, and form a peculiar radiated circle round the face. The eyes are large, black and prominent. The ears are short, rounded, edged with white, and terminated by tufts of black hair. There are six short rounded incisors in each jaw, two canines, which are long and sharp, and six molars on each side. The hair on the legs is short and of a yellowish tinge. The feet are five-toed, with large strong claws. The soles are bare, and are plantigrade―applied to the ground throughout the whole of their length―and the hind ones are longer than the fore ones.

In general build, the binturong is essentially like Paradoxurus and Paguma, but more massive in the length of the tail, legs and feet, in the structure of the scent glands, and in the larger size of the rhinarium, which is more convex with a median groove being much narrower above the philtrum. The contour hairs of the coat are much longer and coarser, and the long hairs covering the whole of the back of the ears project beyond the tip as a definite tuft. The anterior bursa flap of the ears is more widely and less deeply emarginate. The tail is more muscular, especially at the base and, in colour, generally like the body, but commonly paler at the base beneath. The body hairs are frequently partly whitish or buff, giving a speckled appearance to the pelage, sometimes so pale that the whole body is mostly straw-coloured or grey. The young are often paler than the adults, but the head is always closely speckled with grey or buff. The long mystacial vibrissae are conspicuously white, and there is a white rim on the summit of the otherwise black ear. The glandular area is whitish.

The tail is nearly as long as the head and body. The body ranges from 28 to 33 in and the tail is from 26 to 27 in long. Some captive binturongs measured from 75 to 90 cm in head and body, with a tail of 2 ft. The mean weight of captive adult females is 21.9 kg, with a range from 11 to 32 kg. Captive animals often weigh more than their wild counterparts. 12 captive female binturongs were found to weigh a mean of 24.4 kg while 22 males weighed a mean of 19.3 kg. In one study, the estimated mean weight of wild females was 10.5 kg. However, seven wild male binturongs in Thailand were found to weigh a mean of 13.3 kg, while one female was of similar weight at 13.5 kg. One estimate of the mean body mass of wild binturongs was 15 kg.

Both sexes have scent glands—females on either side of the vulva, and males between the scrotum and penis. The musk glands emit an odor reminiscent of popcorn or corn chips, described as "ltpɨt" by the Malaysian Jahai people, likely due to the volatile compound 2-acetyl-1-pyrroline in the urine, which is also produced in the Maillard reaction at high temperatures. Unlike most other carnivorans, the male binturong does not have a baculum.

Distribution and habitat
The binturong occurs from India, Nepal, Bangladesh, Bhutan, Myanmar, Thailand and Malaysia to Laos, Cambodia, Vietnam and Yunnan in China, Sumatra, Kalimantan and Java in Indonesia, to Palawan in the Philippines.

It is confined to tall forest. In Assam, it is common in foothills and hills with good tree cover, but less so in the forested plains. It has been recorded in Manas National Park, in Dulung and Kakoi Reserved Forests of the Lakhimpur district, in the hill forests of Karbi Anglong, North Cachar Hills, Cachar and Hailakandi Districts. It was also recorded in Kaziranga National Park in the year 2024.

In Myanmar, binturongs were photographed on the ground in Tanintharyi Nature Reserve, at an elevation of 60 m in the Hukaung Valley, at elevations from 220 – in the Rakhine Yoma Elephant Reserve, and at 580 m and at three other sites up to 1190 m elevation.

In Thailand's Khao Yai National Park, several individuals were observed feeding in a fig tree and on a vine.

In Laos, they have been observed in extensive evergreen forest. In Malaysia, binturongs were recorded in secondary forest surrounding a palm estate that was logged in the 1970s.

In Palawan, it inhabits primary and secondary lowland forest, including grassland–forest mosaic from sea level to 400 m.

Ecology and behavior


The binturong is active during the day and at night. Three sightings in Pakke Tiger Reserve were by day. Camera traps set up in Myanmar captured thirteen animals, one around dusk, seven at night and five in broad daylight. All the photographs were of single animals, and all were taken on the ground. Because binturongs are not very nimble, they may have to descend to the ground relatively frequently when moving between trees.

Five radio-collared binturongs in the Phu Khieo Wildlife Sanctuary exhibited an arrhythmic activity dominated by crepuscular and nocturnal tendencies with peaks in the early morning and late evening. Reduced inactivity periods occurred from midday to late afternoon. They moved between 25 m and 2698 m daily in the dry season and increased their daily movement to 4143 m in the wet season. Ranges sizes of males varied between 0.9 and 6.1 km2. Two males showed slightly larger ranges in the wet season. Their ranges overlapped between 30 and 70%. The average home range of a radio-collared female in the Khao Yai National Park was estimated at 4 km2, and the one of a male at 4.5 to 20.5 km2.

The binturong is essentially arboreal. Pocock observed the behaviour of several captive individuals in the London Zoological Gardens. When resting, they lay curled up with their heads tucked under their tails. They seldom leaped, but climbed skilfully, albeit slowly, progressing with equal ease and confidence along the upper side of branches or, upside down, beneath them. The prehensile tail was always ready as an aid. They descended the vertical bars of the cage head first, gripping them between their paws and using the prehensile tail as a check. They growled fiercely when irritated, and when on the prowl they periodically uttered a series of low grunts or a hissing sound, made by expelling air through partially opened lips.

The binturong uses its tail to communicate. It moves about gently, clinging to a branch, often coming to a stop, and often using the tail to keep balance. It shows a pronounced comfort behaviour associated with grooming the fur, shaking and licking its hair, and scratching. Shaking is the most characteristic element of comfort behaviour.

Diet
The binturong is omnivorous, feeding on small mammals, birds, fish, earthworms, insects and fruits. It also preys on rodents. Fish and earthworms are likely unimportant items in its diet, as it is neither aquatic nor fossorial, coming across such prey only when opportunities present themselves. Since it does not have the attributes of a predatory mammal, most of the binturong's diet is probably of vegetable matter. Figs are a major component of its diet. Captive binturongs are particularly fond of plantains, but also eat fowls' heads and eggs.

The binturong is an important agent for seed dispersal, especially for those of the strangler fig, because of its ability to scarify the seed's tough outer covering.

In captivity, the binturong's diet includes commercially prepared meat mix, bananas, apples, oranges, canned peaches and mineral supplement.

Reproduction
The average age of sexual maturation is 30.4 months for females and 27.7 months for males. The estrous cycle of the binturong lasts 18 to 187 days, with an average of 82.5 days. Gestation lasts 84 to 99 days. Litter size in captivity varies from one to six young, with an average of two young per birth. Neonates weigh between 280 and 340 g, and are often referred to as shruggles. Fertility lasts until 15 years of age.

The maximum known lifespan in captivity is thought to be over 25 years of age.

Threats
Major threats to the binturong are habitat loss and degradation of forests through logging and conversion of forests to non-forest land-uses throughout the binturong's range. Habitat loss has been severe in the lowlands of the Sundaic part of its range, and there is no evidence that the binturong uses the plantations that are largely replacing natural forest. In China, rampant deforestation and opportunistic logging practices have fragmented suitable habitat or eliminated sites altogether. In the Philippines, it is captured for the wildlife trade, and in the south of its range it is also taken for human consumption. In Laos, it is one of the most frequently displayed caged live carnivores and skins are traded frequently in at least Vientiane. In parts of Laos, it is considered a delicacy and also traded as a food item to Vietnam.

The Orang Asli of Malaysia has the tradition of keeping binturongs as pets.

The binturong is also sometimes kept captive for production of kopi luwak.

Conservation
The binturong is included in CITES Appendix III and in Schedule I of the Indian Wild Life (Protection) Act, 1972, so that it has the highest level of protection. In China, it is listed as critically endangered. It is completely protected in Bangladesh, and partially in Thailand, Malaysia, Vietnam and Indonesia. It is not protected in Brunei.

World Binturong Day is a yearly event held in several zoos and is dedicated to binturong awareness and conservation. It takes place every second Saturday of May.

In captivity
Binturongs are common in zoos, and captive individuals represent a source of genetic diversity essential for long-term conservation. Their geographic origin is either usually unknown, or they are offspring of several generations of captive-bred animals.