The Bornean orang utan is on the verge of extinction, with a top conservationist body also warning that the whale shark - the world's biggest fish - and a hammerhead shark species were endangered.
In an update to its "Red List" of threatened species, the International Union for the Conservation of Nature (IUCN) said growing human pressure was driving the three species ever closer to destruction.
Here are six other animals which are close to extinction:
1. Black Rhinoceros
- Location: Southern and eastern Africa, including Kenya, Tanzania, Cameroon, Namibia, South Africa, Zimbabwe and Angola.
- Population: Estimated at between 2,000 and 5,000.
Listed as critically endangered, the black rhinoceros is smaller than the white rhinoceros, although adults can still reach 1.5 metres in height and weigh in at 1.4 tonnes.
The species is distinguished from the white rhino by a prehensile upper lip (which explains the alternative name of hook-lipped rhino), which it uses to feed on twigs of woody plants and a variety of herbaceous plants.
The front horn is the longer of the two horns, averaging 50cm in length.
Large-scale poaching has seen rhino populations dwindle dramatically. The escalating demand in Asia for the use of rhino horn for traditional Chinese medicine and dagger handles has caused black market prices to surge.
2. Indian Vulture
- Location: Villages, towns and cities near cultivated and wooded areas in south-eastern Pakistan and India.
- Population: Like other vulture species, the Indian Vulture significantly declined since the late 1990s, losing as much as 99 per cent of its population.
The long-billed Indian vulture has a bald head, very broad wings and short tail feathers.
It is smaller and less heavily built than the Eurasian Griffon, usually weighing between 5.5 and 6.3 kg and measuring 80-103 cm long and 1.96m to 2.38m across the wings.
By mid-2000, Indian vultures were being found dead or dying in Pakistan and throughout India. The cause of the deaths was the anti-inflammatory drug diclofenac, used to treat domestic livestock. The dead birds were poisoned by the drug, which caused kidney failure.
3. Hector's Dolphin
- Location: Coastal regions of New Zealand.
- Population: The latest published estimate of South Island Hector's dolphins is 7,270. This is just 27 per cent of the population estimated in 1970, which was about 30,000.
Hector's dolphin is the smallest of the dolphins, with mature adults growing up to 1.6m long and weighing between 40kg and 60kg.
Females are slightly longer and heavier than males. The body shape is stocky with no discernible beak, with a rounded dorsal fin being its most distinctive feature.
Natural predators of Hector's dolphins include sharks and killer whales. Remains of Hector's have been found in sevengill and blue shark stomachs.
The biggest threat to this endangered species is inshore fishing but they are also at risk from a parasitic infection which causes them to die from toxoplasmosis.
4. Asian Elephant
- Location: Found in isolated populations in 13 tropical Asian countries, including China, India and Malaysia.
- Population: Declined by at least 50 per cent in last 60 years. In 2003, the wild population was estimated at between 41,410 and 52,345.
The Asian Elephant is smaller than its African savannah relative; the ears are smaller and the back is more rounded. Their feet have more nail-like structures than those of African elephants - five on each forefoot, and four on each hind foot.
The numbers of Asian Elephants have been decimated by habitat loss, degradation, and fragmentation, driven by an expanding human population. This leads to elephants becoming increasingly isolated in the remaining fragmented habitat, causing them to come into conflict with local farmers.
Poaching for ivory is also a threat. Since only males have tusks, breeding rates are affected as populations can become extremely skewed towards females.
- Location: The largest of all cats once thrived throughout central, eastern and southern Asia, but currently survives only in scattered populations.
- Population: A 2016 global census estimated the population of wild tigers at approximately 3,890.
The largest tigers can reach a total body length of up to 3.38m and have weighed up to 388.7 kg in the wild.
The Caspian, the Java and the Bali tiger have already become extinct in the last 80 years, and of the remaining six subspecies, the South China tiger has not been seen for many years.
Poaching and illegal killing are the major threats to the survival of wild tigers. Habitat loss and overhunting of tigers as well as their natural prey species have reduced their numbers further.
6. Pygmy Hippo
- Location: Restricted to the West African countries of Liberia, Côte d'Ivoire, Guinea and Sierra Leone.
- Population: The World Conservation Union estimates that there are fewer than 3,000 pygmy hippos remaining in the wild.
The pygmy hippo is reclusive and nocturnal. Like its larger cousin, it is semi-aquatic, needing water to lower its body temperature and keep its skin moist.
They are herbivores, feeding on ferns, broad-leaved plants, grasses, and fruits found inforests.
Pygmy hippos are primarily threatened by loss of habitat, as forests are logged and converted to farm land, and are also vulnerable to poaching, hunting for bushmeat, natural predators and war. They are among the species illegally hunted for food in Liberia.
Sources: IUCN, World Wildlife Fund, BirdLife