By Alex Kirby BBC News Online environment correspondent

He's off: One tiger eludes the poachers

The tiger, a male, was discovered by two students who alerted US scientists and Russian officials to its plight.

It was given a radio collar before it was set free so it can be tracked as it roams the forest where it grew up.

There are thought to be only about 400 Siberian tigers left in the wild, with poaching for their skins and body parts one of the greatest threats they face.

Alarm calls

The rescued animal, whose age is put at from eight to 10 years, was found by the students as they hiked in the woods last week.

Hearing it roaring in distress they went to see what had happened and found it with the snare wrapped around its body.

He bounded about 20 metres into the forest, stopped, turned and growled, before walking calmly away John Goodrich, WCS

They notified forest guards in a cabin a few miles away, who contacted officials from the Russian Ministry of Natural Resources and scientists from the Wildlife Conservation Society, based at the Bronx Zoo in New York.

The rescue team anaesthetised the tiger, and found that although it had numerous abrasions from the snare it appeared otherwise healthy.

They took it to a holding area to make sure it had no internal injuries, before fitting it with the collar to enable WCS scientists to track it as part of a long-term study aimed at giving the tigers better protection.

Back to the forest

John Goodrich of WCS said: "The release went well. The tiger leapt from his cage about a minute after the door was opened.

"He then bounded about 20 metres (65 feet) into the forest, stopped, turned and growled, before walking calmly away."

There are thought to have been about 100,000 tigers in 1900, stretching from eastern Asia to Turkey.

Conservationists believe their numbers have fallen by more than 90% since then, leaving about 5-7,000 animals in the wild.

In that time three sub-species have become extinct - the Java, Bali and Caspian tigers.

The South China tiger is now reduced to an estimated 20-30 individuals, with the Siberian (known also as the Amur tiger: it lives in China and North Korea as well as the Russian far east) the next most threatened.

Poachers sell their body parts for use in traditional far eastern medicine, and the skins always fetch a good price.