Over the last century, tiger habitats     1     (fall) by around 95 percent, and there are now     2     (few) than 4,000 tigers alive in the wild, reports the World Wildlife Fund (WWF). Of the nine species of tiger, three have already died out and the remaining six     3     (consider) endangered. The most common cause of the decrease of a tiger species is us human, whether from hunting or destroying their habitats.

Siberian tigers, also known     4     Amur and Manchurian tigers, were once found throughout the Russian Far East, northern China and the Korea, according to the WWE. By the 1940s,     5     (hunt) had reduced their number to 40, but Russia has since taken steps towards protecting them, and their numbers have risen about 500 as     6     result Challenges to their continued existence include illegal hunting     7     not having enough food. At the moment, Siberian tigers represent the largest tiger population on the planet.

Of all tiger subspecies, the South China tiger may be at the greatest risk of     8     (extinct). The WWF reports there are just 30 to 80 South China tigers     9     (leave) in the world, all of     10     are in captivity (被圈养); the South China tiger hasn’t been seen in the wild in over a quarter-century.

The giant panda, also    1     (know) as panda bear or simply panda, is a bear native     2       south central China. For the past many years, the giant panda    3     (drive) out of the lowland areas where it once lived as a result of farming, deforestation and other    4       (develop). Wild population estimates vary: one estimate shows that there are about 1,590 individuals    5     (live) in the wild, while a 2006 study estimated that this figure could be as high as 2,000 to 3,000. Some reports also show that     6       number of giant pandas in the wild is on the rise.

The West first learned of the giant panda on March 11, 1869,     7     the French missionary (传教士) Armand David received a panda skin from a hunter. In 1936, Ruth Harkness became the first Westerner    8    (bring) a live giant panda named Su Lin to the Brookfield Zoo in Chicago. To protect the pandas, in 2012, Earthwatch Institute, a global non-profit organisation that teams volunteers with scientists to conduct important     9     (science) research, launched a program called “On the Trail of Giant Pandas”. This program allows volunteers to work up close with pandas cared for in captivity (圈养), and help them    10     (gradual) adapt to life in the wild.