A list of the 100 most threatened species has been released by the Zoological Society of London and the International Union for Conservation of Nature. It lists species that are close to extinction.
Hibiscadelphus woodii is a species of small tree known only from the Kalalau Valley on Kauai - one of the Hawaiian Islands. It was discovered in 1991 and is threatened by other plants and wild goats.
The Tarzan chameleon lives on Madagascar, inhabiting a range of about 10 sq km. Its forest home has been shrinking fast due to human activities such as logging.
The Santa Catarina's guinea pig can only be found on the small island of Moleques do Sul in Brazil. Conservationists are worried that people could hunt them as they are allowed to go on the island.
There are thought to be as few as 250 adult Sumatran rhinos which means they are classified as Critically Endangered. The major human threat to them is from hunting. Many people want to use their horns in medicine.
This type of pheasant called the Edwards's pheasant lives in the damp mountain forests of central Vietnam. The bird has not been seen sighted since 2000, and there are suggestions it may already be extinct in the wild.
The striking red-finned blue-eye fish is found only in a complex of freshwater springs in north-east Australia. The species is being threatened by the introduced mosquito fish and by the practice of draining water from a natural basin associated with the springs.