A new sub-population of a Critically Endangered species of monkey has been recorded in north-western Vietnam.

Biologists from Fauna and Flora International said they had found up to 20 Tonkin snub-nosed monkeys in a remote forest.

The team said the new group offered a ray of hope because it included three infants, suggesting that the monkeys were breeding and increasing in number.

Until now, fewer than 250 of the primates were thought to exist.

"When I saw the Tonkin snub-nosed monkeys, I was overjoyed," said biologist Le Khac Quyet.

"This new discovery further underlines the importance of learning more about the monkeys' range and distribution.

"There is still time to save this unique species, but with 200 or so left and the threat still strong, we need to act now," he added.

Under pressure

The IUCN Red List of Threatened Species lists the monkeys as Critically Endangered because their numbers have continued to decline as a result of intensive hunting and deforestation.

Until now, the monkeys had only been recorded in a few north-eastern areas within
© L.QUYET/FFIHunting and deforestation has led to a continued decline in the species
Vietnam, with no group exceeding 50 mature adults.

The loss of habitat and human encroachment had "dramatically restricted" the animals' distribution, the Red List warned.

It also said that the creatures' inquisitive nature also meant that they did not flee when approached by humans, increasing the risk of being shot by hunters.

However, Fauna and Flora International (FFI) hopes the discovery of the new sub-population will lead to increased efforts to protect the primates' remaining habitat.

"All recent indications suggest that we have a fantastic opportunity to secure this population and significantly increase the chances of survival of this species," explained Paul Insua-Cao, FFI's Vietnam primate programme manager.

Biologists observing the monkeys also found that they were more wary of people, issuing warning signs to each other.

The FFI team suggested that this group had associated humans with danger, perhaps as a result of ongoing threats from hunters.

A global assessment of the world's primates published in August warned that 48% of the order faced extinction.

The outlook, described as depressing by conservationists, warned that the main threat was habitat loss, primarily deforestation.

Other threats include hunting of primates for food and the illegal wildlife trade.

The FFI team hopes its work, co-funded by the UK government, with local people will ease the pressures on the Tonkin snub-nosed monkeys' habitat.

Measures including curbing the growing of crops in the area's tropical forests and confiscating hunters' guns have already been introduced since the new sub-population was first recorded in April 2008.