The Sunda clouded leopard is a medium-sized wild cat native to Borneo and Sumatra. It is an overall grayish-yellow or gray hue. It has a double midline on the back and is marked with small irregular cloud-like patterns on the shoulders. These cloud markings have frequent spots inside and form two or more rows that are arranged vertically from the back on the flanks. The Sunda clouded leopard has a stocky build and its canine teeth are 2 in (5.1 cm) long, which, in proportion to the skull length, are longer than those of any other living cat. Its tail can grow to be as long as its body, aiding balance.
Sunda clouded leopards are restricted to the islands of Borneo and Sumatra. In Borneo, they live in lowland rainforest, and in logged forest. In Sumatra, they prefer to live in hilly, montane areas.
Sunda clouded leopards are very secretive and their habits are largely unknown. It is assumed that they are generally solitary and nocturnal. However, in areas where there are no larger cats, clouded leopards are more active during the day. They hunt mainly on the ground and use their climbing skills to hide from dangers.
Sunda clouded leopards may breed year-round, however, the peak usually takes place from December through March. The female gives birth to a litter of 1-5 cubs after the gestation period that lasts about 85-95 days. Baby clouded leopards are born helpless. Their eyes are closed and they have no teeth. The young are usually weaned and become independent from their mother at age of 10 months. Reproductive maturity is reached when they are 2 years old.
Sunda clouded leopards being strongly arboreal are forest-dependent are increasingly threatened by habitat destruction following deforestation in Indonesia as well as in Malaysia. The population of Sunda clouded leopards in Sumatra and Borneo has been estimated to decrease due to forest loss, forest conversion, illegal logging, encroachment, and possibly hunting. In Borneo, forest fires pose an additional threat, particularly in Kaltim and in the Sebangau National Park. There have also been reports of poaching of Sunda clouded leopards in Brunei's Belait District where locals are selling their pelts at a lucrative price.
According to the IUCN Red List, the total population size of the Sunda clouded leopard is below 10,000 individuals. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List and its numbers today are decreasing.