DNA test shows Sumatran tiger a separate species

DNA test shows Sumatran tiger a separate species

WASHINGTON (Reuters): DNA evidence shows that Sumatran tigers are a separate species from other tigers, which means extra efforts are needed to save them, scientists said on Monday.

They said that while all tigers are under threat of extinction, Sumatran tigers may be a special case because there are so few of them in zoos.

"The discovery that they represent a unique species indicates an urgent need to increase conservation management both on the Indonesian island of Sumatra, the only location where these tigers are found, and in zoos around the world," the American Museum of Natural History, which helped sponsor the study, said in a statement.

The museum's Joel Cracraft and colleagues collected blood from 34 captive tigers and a lion for comparison.

They looked at the mitochondrial DNA -- genetic material that is passed down intact from the mother. It showed that the Sumatran tiger is distinct enough from other tigers to be considered a separate species.

According to the museum, the tiger has always been considered a single species with five subspecies -- the South China tiger, the Siberian tiger, the Bengal tiger, the Indochinese tiger and the Sumatran tiger. The Bali tiger, the Caspian tiger and the Javan tiger have all become extinct.

Cracraft's team, which published their findings in the new journal Animal Conservation, put out by the London Zoological Society, said there were only about 400 to 500 Sumatran tigers left in the wild, and 235 in captive breeding programs.

Sumatran tigers are the smallest of all tigers, weighing 220 to 310 pounds (100 to 135 kg) and growing up to eight feet (2.4 metres) in length. A male Siberian tiger can grow to 11 feet long (3.35 metres) and weight up to 675 pounds (306 kg).

Cracraft said Sumatran tigers probably became isolated from other tigers between 6,000 and 12,000 years ago.