Helarctos Malayanus

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in biology, Helarctos Malayanus (Alias:Sun bear) is a species in the family Ursidae (the only species in the genus Helarctos) occurring in the tropical forests of Southeast Asia. The sun bear is a carnivorous mammal of the family Ursidae. The body is fat, the neck is short, the eyes and ears are small; the head is short and round; the whole body is black and smooth; the nose and lips are brownish-yellow, naked and hairless; the eye circles are grayish brown, and there are short webs at the base of the toes; there is a whorl of hair in the center of the chest spot. The skin around the neck is extremely loose, and the chest is usually dotted with a conspicuous stripe, which is light brown or yellow-white; Males are generally larger than females. The sun bear is the smallest bear in the world.

The sun bear is one of the most precious and rare species in the world. His body is smart and strong, and he is very popular among people. However, human activities threaten the survival of sun bears, resulting in the loss of their habitat due to deforestation. The sun bear is classified as vulnerable (VU) in the "IUCN Red List of Threatened Species". It is listed as a first-level protected wild animal in China.

The sun bear is named so for its characteristic orange- to cream-coloured, crescent-like chest patch. The generic name Helarctos comes from two Greek words: ήλιος (hēlios, related to the sun) and αρκτος (arctos, bear). Another name is honey bear, beruang madu in Malay and Indonesian, in reference to its habit of feeding on honey from honeycombs. "Honey bear" can also refer to the kinkajou.

shape

Male sun bears are generally larger than females. The length of the head and body is 1000-1400 mm; the length of the tail is 30-70 mm; the length of the hind legs is 180-210 mm; the length of the ears is 40-60 mm; the total length of the skull is 230-290 mm; the weight is 25-65 kg. The head and neck are short and round. The nose and the upper lip near it are completely naked, and there is no clear dividing line between the tip of the nose and the hair area behind it. The eyes are small, the ears are small, and the tail is short. The limbs are strong and strong. The front and rear feet each have 5 toes. The front paws are longer than the rear paws. The soles of the feet are thick and hairless. The palm pads are integrated into two expanded and unified carpal pads (forefoot) or expanded into a large tarsal pad (hindfoot). The bases of the finger processes or toe processes are connected to each other by short webs, so the finger processes or toe processes are more flexible than other bears. The female has two pairs of nipples on her abdomen. The front pair is well developed and as big as a jujube. The hair is short and sparse. In summer, the back hair is only 14 mm long, and gradually shortens forward. Near the tip of the nose, the hair length is less than 5 mm. There are two symmetrical hair whirlpools on the shoulders. Some of the hair streams shooting out from here reach the top of the head, and some go down the side of the neck and meet the upward hair stream of the hair whirlpool in the center of the chest spot. A significant hair ridge 20-30 mm high is formed at the intersection. This hair ridge goes up from behind the ear to the top of the head and is connected to the hair ridge on the opposite side. Therefore, judging from the direction of the hair on the shoulders, neck and top of the head, the main vortices are forward and outward, which is different from other bears whose hair on the head and neck is draped uniformly towards the back. The hair on the waist and hips is shorter, about 10 mm long. The length of the hair on the chin, throat and chest is similar to that of the head and neck. The abdominal hair is sparse and 40-50 mm long. The hair around the tail is as long as the abdominal hair, and its density is similar to that of the back hair. The sun bear is the smallest bear in the world.

Coat color

The whole body is shiny black, but the nose and mouth tube are dark milky yellow or brown. The upper part of the nose and lips is gradually mixed with the brown hair base of the head, and the closer to the eyebrows, the more yellowish brown. Eye circles brownish gray. The chest zebra is horseshoe-shaped, slightly wider on the right side than the left side, darker brown and dyed with brown-red. The rump and paws are slightly tan.

skull

The nose and forehead are extremely shortened, the muzzle is slightly square, and the width of the muzzle is greater than the width between the orbits. The zygomatic arch is very expanded, and when viewed from above, it lies within a perfect circle. Except for the last 30 mm (near the occiput) of the crest of the head that healed into a single sagittal ridge, none of the parietal ridges healed. It starts from the front 1/3 of the parietal bone and gradually spreads forward and outward toward the postorbital process. It bifurcates into two branches about 30 mm away from the postorbital process, and extends forward and ends at the front of the postorbital process. edge and trailing edge. Mandible short and thick. The mandibular symphysis suture is extremely short and its slope is much higher than that of other bears.

teeth

There are 3 pairs of incisors, the outermost pair is extra large, and the inner 2 pairs are smaller and nearly equal in size. The canine teeth are thick and short, and the tips of the teeth are easily worn. There are 4 premolars on each side of the upper and lower jaws. However, in the skull specimens from Yunnan, there are only 2 in the left upper jaw. The first upper premolar is normal, and the fourth upper premolar has only a broken root. Among the 4 premolars in the right upper jaw, the second upper premolar is extremely degraded. , only one tooth tip is exposed, and it is located on the outside of the tooth row. The upper cleft tooth is very large, with 3 cusps. The front cusp is about the same size as the first upper premolar, and the original cusp is low and inconspicuous. Both upper molars have 4 cusps, the outer 2 are slightly higher than the inner 2, and a low longitudinal alveol is formed in the center of the crown surface. All teeth are square. However, the sub-cusp of the second upper premolar extends particularly backward, forming an irregular oblique rhombus shape. The lower incisors and lower canines are similar to those of the upper jaw, except that the third lower incisor is only slightly larger than the two inner lower incisors. There are 4 lower premolars. Among the 3 lower molars, the third lower molar is the smallest and approximately round in shape. Gear type: 3.1.3.2/3.1.3.3=38.

distribution range

Sun bears are mainly distributed in Southeast Asia and South Asia. Historically, it was distributed in Sichuan, northwestern and southern Yunnan, and southeastern Tibet in China; extending to Indo-China, Sumatra, and Borneo.

Specific countries

Existing: China, Bangladesh, Brunei, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Thailand, Vietnam.

Extinct: Singapore.

The sun bear is a typical forest-dwelling animal. It mainly inhabits dense tropical and subtropical rainforests and evergreen broad-leaved forests at an altitude of 0-1350 meters. Sun bears mainly move in native forests and are damaged (such as logging). This species is not found in habitats. However, there are also reports that sun bears inhabit coconut plantations, lowland mountains and swamp forests up to 2,400 meters above sea level.

behavioral rhythm

Sun bears generally live alone and are ferocious. In the absence of human interference, it feeds mainly during the day, but near human settlements it is exclusively nocturnal. It is highly arboreal and can quickly climb trees to forage for fruits and insect nests. It uses branches to build large nest platforms as a resting place. In addition, the diurnal behavioral rhythm of sun bears shows a single distribution pattern, mainly focusing on diurnal activities. Sun bears will have an activity peak in the morning, and another after 13:00, which will last until dusk. After 18:00, the activity will decrease, and after 21:00, the activity of sun bears will decrease to the lowest (<20%). . Sun bears’ active behavior accounts for 40-70% from May to November, with an average activity level of 52%, and the highest activity frequency in September (70%).

Home range characteristics

Wong (2002) used radio telemetry technology to record and analyze the home range areas of six sun bears. 95% of the calculation results show that the average home range area of sun bears is 14.8±6.1 square kilometers, and the home range covers rainforests and logging areas. There is a certain degree of overlap in the home ranges of different sun bear individuals, but no overlap was found in 25% of the core area. The core area of the sun bear family range is 0.68±0.32 square kilometers. The sun bear's daily movement distance is 1.45±0.24 kilometers. This distance is affected by food availability .

foraging activity

Omnivorous, with a narrow diet, its main food is insects, honey and fruits. It feeds on more than 100 species of insects, especially social insects such as ants, termites and bees. It uses its strong claws to dig open the insect nest, and then uses its extremely long tongue to lick up the insect adults, larvae, eggs, honey, honeycomb, beeswax and fruit fat. Fruit is also an extremely important food. There are more than 40 types of edible fruits, the most important of which is the banyan tree fruit. Occasionally prey on other invertebrates such as earthworms and scorpions, reptiles (including small turtles), gnats, and bird eggs. They rarely eat plant food, but they like to eat the buds (coconut hearts) of coconut trees. Without the coconut hearts, the coconut trees cannot survive, causing conflicts with plantation owners. They also eat orchard fruits and crops such as sugar cane, potatoes and cassava. It basically does not prey on farmed animals, but occasionally attacks poultry houses. Picking up human waste, especially during seasons when natural food is scarce.

reproduce

Sun bears are in heat and mate from June to August, and their gestation period is about 6-7 months. They give birth to 2 cubs per litter, and occasionally 3-5 cubs. Bear mothers also have delayed implantation of fertilized eggs. There have been records in zoos outside China showing that some female bears were pregnant for as long as 174-240 days. A mother bear can give birth to about two cubs at a time, sometimes three. The cubs are about 2-5 months old and can go out with the mother bear. Newborn bear cubs are very weak, weighing only about 300 grams, and have no hair on their bodies. They will live with their mothers until they reach adulthood before living independently.

life

The sexual maturity of sun bears generally takes 3 years, and some may take 6 years (2372 days). Females are earlier than males. The general lifespan is about 20 years, and in captivity, their longest lifespan is about 24 years.

protection level

In 1972 and 1973, the sun bear was listed as a protected animal in Malaysia and Indonesia.

In 1989, it was listed as a first-level national key protected animal in China.

Listed in the "Red List of Chinese Species" (1996), assessment level - Endangered Species (EN).

It is listed in the first level of China's "List of National Key Protected Wild Animals" (February 5, 2021).

Listed in Appendix I, Appendix II and Appendix III of the 2019 version of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Listed in the "World Conservation Union Red List of Threatened Species" (IUCN) 2016 ver 3.1 - Vulnerable (VU).

Cause of Endangerment

The main factor threatening the survival of sun bears is human activities, including habitat loss caused by deforestation. Sun bears, the world's smallest bears, are facing extinction due to deforestation and poaching in Southeast Asia. In addition, Eastern medicine believes that the green bile of sun bears can be used to treat eye problems, liver and other diseases. Bear paws are considered a delicacy on the table, so sun bears are often poached.

Population status

A camera-based mark-recapture survey in Thailand estimated population densities per 100 km2 at two sites within Khao Yai National Park to be 4.3 (95%Cl 1.6-11.6) and 5.9 (95%Cl 2.3-15.4) (Ngoprasert et al., 2012). In the Harapan rainforest of southern Sumatra, a camera-based study estimated a sun bear density of 26 per 100 square kilometers, 4-5 times higher than the density estimated in Thailand (Lee 2014, unpubl.data).

In Thailand, sun bear populations have declined in some locations, such as Khao Yai National Park, where the camera trap photo encounter rate fell by almost two-thirds, from 0.73 per 100 days (1999-2003) to 0.27 (2003-2007) (Lynam et al., 2003, Jenks et al., 2011). But other populations appear to be doing better, with stable photo encounter rates in Kui Buri National Park and Thung Yai Naresuan Wildlife Sanctuary (Steinmetz, unpublished data). An early systematic mammal status assessment study of native species in Thung Yai Naresuan Wildlife Sanctuary, Thailand, estimated that sun bear populations declined by more than 40% in the 20 years from 1984 to 2004 (Steinmetz et al. 2006). But since then, improvements in conservation and community engagement appear to have had a positive impact. In West Sumatra, repeated camera capture surveys using an occupancy-based sampling frame revealed that Malay New Zealand numbers declined over a 7-year period due to high levels of deforestation (Wong et al. 2013)