tailieunhanh - bbc wildlife magazine october 2010 phần 4

? thanh niên, người lớn, chuyên nghiệp cũng như người đi xe đạp bình thường. Tạp chí này được làm đầy với các nội dung quốc tế và địa phương tốt nhất cho mọi phần tử của các tay đua xe đạp cuộc đời từ kỹ thuật đào tạo và thông tin tập thể dục để truyền cảm hứng cho câu chuyện quan tâm của con người, | AGENDA WorldMags Mike Wilkes Terry Whittaker Rare gibbons on song Listening - not looking -helps scientists find new population of Critically Endangered ape. Scientists have discovered the largest-known remaining population of the Critically Endangered northern whitecheeked crested gibbon in a remote area of northern Vietnam. The discovery of an estimated 455 individuals in one unbroken area of forest represents nearly 70 per cent of the total number of this gibbon in Vietnam. It is also the only confirmed viable population of the species according to scientists from Conservation International CI who discovered the gibbons in Pù Mát National Park near the border with Laos. Historically distributed in China Vietnam and Laos i this rare ape is thought to be functionally extinct in China. Its status in Laos is unknown due to a lack of research though significant numbers may still survive says CL Gibbons persist in this area only because of its extreme remoteness said Ben Rawson who led the research. An earlier visual survey of BACKGROUND lllllllllll Gibbons are considered to be lesser rather than great apes such as gorillas and orangutans. They differ from great apes in being smaller exhibiting monogamist behaviour and in certain anatomical details. Gibbons are the most arboreal apes and can swing through the treetops at 50kmph. northern Vietnam discovered no large groups of gibbons so in 2010 the focus was changed to Pù Mát and a new technique was adopted - auditory sampling . Gibbons are highly arboreal and territorial and communicate with prolonged vocalisations as they swing through the trees. As a result they are extremely difficult to see so the animals were counted by recording and analysing their songs. We found only one group visually - the rest were detected through their vocalisations Rawson said. Most of the gibbons survive at altitudes above 700m. They were under strong hunting pressure in the early 1990s but that threat has diminished .