- Associated Press - Monday, July 18, 2011

HANOI, VIETNAM (AP) - Conservationists listening to a critically endangered primate’s morning calls in central Vietnam’s mountains heard a surprising response. About 455 animals were counted there based on their calls, making it the largest known population of northern white-cheeked crested gibbons.

Wildlife group Conservation International conducted the census in 2010 by recording the loud song-like vocalizations the gibbons use to mark territory and attract and keep mates.

The primates were in 130 different groups living in thick jungle of the mountains near the Laos border, the group said in a statement Monday. Earlier surveys elsewhere in Vietnam had not documented any populations larger than a dozen groups.

The primate was known to exist in China, Vietnam and Laos. It is considered functionally extinct in China, but its numbers are unclear in Laos because little research has been conducted there.

The count was conducted in Pu Mat National Park in Nghe An province, and the conservation group expressed concerns about planned road projects that could destroy habitat in the place where the species has its last known viable population.

“The major issue will be the hunting of these gibbons that were previously protected by the harsh terrain,” Luu Tuong Bach, a Conservation International consultant who led the surveys, said in the statement. “Without direct protection in Pu Mat National Park, it is likely that Vietnam will lose this species in the near future.”

All of the 25 gibbon species existing worldwide are threatened, and eight of the Indochinese crested gibbon species are near extinction, including the northern white-cheeked crested gibbon.