Less than 200 Tonkin snub-nosed monkeys are left in the world, all in northeastern Vietnam. Once believed to be extinct, the species' biggest threats are the loss of habitat from illegal logging and hunting. They are one of the 100 most endangered species, according to a report released Sept. 11, 2012, by the Zoological Society of London and the International Union for Conservation of Nature.

There are less than 250 mature Sumatran rhinos left in the world today. They can be found across Sumatra and Borneo in Indonesia. The Sumatran rhinos' biggest threat is poachers who are after their horns. Some Asian countries use rhino horn in traditional medicine to treat fever, rheumatism, gout, and other disorders.

There are believed to be 779 antilophia bokermanni left in the world. They can be found in Brazil and the biggest threat to their survival is the loss of their habitat due to expansion of agriculture, recreational facilities and water diversion.

There are only four Red River giant softshell turtles left in the world. This enormous creature can reach up to 264 pounds with a shell over two feet long. The Red River giant softshell turtle used to be found throughout the Red River in Yunna, China and Vietnam, but can now be found only in a breeding program at the Suzhou Zoo.

Tarzan's Chameleon, whose scientific name is Calumma Tarzan, comes from the rain forests of eastern Madagascar. Slash and burn agriculture is the biggest threat to this rare species.

It is unknown how many angel sharks remain in the world. They used to live in the coastal waters of the Atlantic Ocean as far north as Norway and into the Mediterranean Sea. Today, they're mostly only found in the Canary Islands. The biggest threat to the angel shark's survial is benthic trawling, a fishing method that drags nets along the ocean floor.

There are currently less than 500 pygmy three-toed sloths in the world. They are located on the Isla Escudo de Veraguas in Panama. Although the island is uninhabited, visitors threaten this species with illegal logging of the mangrove forests for firewood and construction.

There are less than 50 coral trees left in the world. The remaining ones can be found Namatimbili-Ngarama Forest in Tanzania

The Luristan newt can be found in three streams in the southern Zagros mountains of Iran, although it spends winters hibernating under rocks in arid shrub lands. There are believed to be less than 1,000 left. The biggest threat to their survival is the pet trade. This species is strikingly colored and has been spotted for sale in markets in Tehran.

The Saola is a relative of the cow and goat and its name represents the only Lao word in the English language. It was discovered in 1992 and has never been seen in the wild by a scientist. The biggest threat to the Saola is hunters, who do not target the Saola but often hit them accidentally. Infrastructure development and agriculture also threatens the Saola's habitat on the Vietnam/Laos border.

The gooty tarantula can be found in several parts of India and it is unknown how many of the species remains. Deforestation and civil unrest in the area is damaging to their habitat and threatening the survival of this rare species.

The vaquita is the world's smallest porpoise and there are less than 200 still in existence. They can be found in the Northern Gulf of California off Mexico. The vaquita commonly drown accidentally in fishermans' nets. The government of Mexico has taken steps to ban fishing gear in the vaquita's territory, but that appears to have only slowed their decline.

There are fewer than 100 spoon-billed sandpiper breeding pairs left and the bird has an annual rate of decline of 26 percent over the last decade. This species breeds in Russia but migrates south to spend the winter in southern and Southeast Asia. The biggest threat to this species is trapping and hunting that occurs in their winter habitat. At the current rate, they could be extinct in 10 years.

It was believed that the greater bamboo lemur was extinct for 50 years before it was rediscovered in 1972. Today there are between 100 and 160 greater bamboo lemurs left. They can be found in the southeastern and southcentral rainforests of Madagascar. The biggest threat to this species is the destruction of their habitat due to slash-and-burn agriculture, mining and illegal logging.