A new report shows that there are just 7,100 cheetahs now left in the wild. Cheetahs are in trouble now.

According to the study, more than half of the world’s surviving cheetahs live in one zone that covers six countries in southern Africa. Cheetahs in Asia have nearly died out. It’s thought that only fewer than 50 cheetahs live in Iran.

The cheetah runs across lands far outside protected areas. Some 77% of their habitat falls outside these protected areas. As a result, the cheetah struggles because these lands are increasingly being developed by farmers and the cheetah’s food is decreasing because of human hunting.

In Zimbabwe, the cheetah population has fallen from around 1,200 to just 170 in 16 years, with the main cause being major changes in land ownership.

Researchers say that the threats cheetahs are facing have gone unnoticed for far too long. “Given the nature of the cheetah, it has been difficult to gather information on them,” said Dr Sarah Durant, the report’s lead author. “Our findings show that the large space requirements for cheetahs and various threats faced by them in the wild mean that they are likely to be in danger of dying out.”

Another big concern about cheetahs has been the illegal trafficking (非法交易) of young cheetahs. The young cats can fetch up to $10,000 on the black market. Some 1,200 young cheetahs are known to have been trafficked out of Africa over the past 10 years but around 85% of them died during the journey.

If the cheetahs are to survive, then immediate efforts must be made.

All animals play. running, rolling and wrestling with each other is a way for them to have fun, of course. But it also seems to be how they communicate and strengthen bonds with each other.

When a dog comes up to another dog, front legs bowed and his tail high, his buddy knows he wants to play. But new research shows that this play behavior is surprisingly similar when horses and dogs play.

To study interspecies communication, Elisabetta Palagi and her colleagues from the University of Pisa found 20 YouTube videos of dogs and horses playing where their interactions lasted at least 30 seconds. They analyzed the videos, looking for specific pattern of play.

They found that while playing, both dogs and horses often had relaxed, open mouths-which is common playful facial expression in mammals. Some also copied each other's movements, like pretending to bite, playing with an object, or rolling on their backs on the ground. A 2,000-pound horse can play with a relatively tiny dog because the two are able to communicate their intentions.

"It's an important study because it shows how two animals who look and behave so differently can nevertheless manage to negotiate how to play in a way that's comfortable for both," Barbara Smuts, a behavioral ecologist at the University of Michigan, told National Geographic.

It's even more noteworthy given the large size difference between horses and dogs. The dog is vulnerable (易受伤的) to injury by the horse, and the horse has a deeply rooted tendency to fear animals that look like wolves."

Next up, the researchers write, is exploring the development and shaping of interspecies communication that “can be at the basis of a universal language of play".

Nola (August 21, 1974 -November 22, 2015) was a northern white rhino (犀牛) who lived at the San Diego Zoo Safari Park near Escondido, California. At her death, she was one of only four remaining northern white rhinos in the world. The other three lived in Kenya. World Rhino Day, held on September 22, is to raise awareness (意识) of the less than 30,000 other rhinos left on Earth.

“Rhinos need our help today, not tomorrow. ” Nola’s lead keeper Jane Kennedy said. “Last year we lost over 1,200 rhinos just in South Africa. If we continue to lose more than 1,000 rhinos a year, in 10 to 20 years all the rhinos on the earth will be gone.”

Unfortunately, most animals are in danger of dying out because of humans. Kennedy says, “Humans have either poached (偷猎) animals, or because there are over seven billion of us, we’ve taken up too much of the world’s resources.” Poachers illegally hunt rhinos for their horns (角). They sell the horns for thousands of dollars per pound, to be used for art, jewelry, and decorations. Experts believe that one rhino is poached every eight hours.

In 1975, the San Diego Zoo Institute for Conservation Research started the Frozen Zoo, a program through which researchers have collected cell samples (细胞样品) from more than 8,000 different types of animals, including the northern white rhino. Scientists hope that by studying the rhino cells, they will get greater understanding of it, and will find ways to increase its numbers.

At the San Diego Zoo, children and adults are welcome to visit and speak with zookeepers to learn about rhinos. For more information, go to www.worldrhinoday.org.