Guam is a beautiful, small island in the Pacific Ocean. You’ll find happy songbirds, clear blue water, and leafy forest there. But the small island has a big problem: snakes. There are about 2 million brown tree snakes living in Guam.

The snakes likely arrived in the 1940s. They probably slipped(滑行) unseen onto ships and planes heading to Guam. Once there, the snakes laid eggs. Snake families grew. The snakes have no natural enemies to eat them on Guam. Soon, the island was covered with these snakes.

The brown tree snake has had a devastating effect. The snakes eat birds. There used to be 12 kinds of birds on the island. But these snakes have killed off nine kinds of the birds. The snakes can grow to be 10 feet long. They often bite humans. They climb onto power lines and make the electricity go out. This causes millions of dollars in damage.

Scientists have tried many different ways to control the number of snakes. They have used snake traps and snake-sniffing dogs. Nothing seemed to work. Nothing, that is, until they found a surprising secret weapon: killer mice.

Scientists found out that there is one easy way to kill brown tree snakes. They could give them a medicine called Tylenol. People take Tylenol for headaches and other pains. Even a little bit of Tylenol can kill a brown tree snake.

But how would scientists get the tree snakes to eat Tylenol? They came up with a plan. First, the experts put the medicine into dead mice. Then they attached each mouse to a mini paper parachute(降落伞). Planes dropped the mice over Guam. The parachutes got caught in the trees. The mice became dinner for the snakes that live there.

Has it worked? So far, research shows that there are fewer snakes because of the mice. The worry is that it may be too late to clear the snakes, but Mr. Vice from Guam’s Department of Agriculture says this should not stop the islanders from trying. “Our long-term goal is to kill the snake off completely,” he says.

For animals that spend most of their lives in the high trees, gaps in the forest might as well be the Grand Canyon. These gaps are especially hard on gibbons(长臂猴); although larger males can leap across some gaps, females and the young can be cut off from food, companions, and even potential mates. Now, a new study suggests a couple of strong ropes could really help bridge the gap.

Gibbons are at risk of extinction across Southeast Asia, largely because of habitat loss. With about 30 individuals left, the Hainan gibbon is considered the rarest primate(灵长类) on Earth. All of these animals live on the Hainan Bawangling National Nature Reserve. In July2014, a typhoon caused landslides across the reserve, creating gaps in the forest that were difficult for these primates to cross.

To help reconnect the habitats, professional tree climbers set up an artificial " bridge"made of two mountaineering-grade ropes across a 15-meter-wide valley. Nearly 6 months later,the gibbons started to use the bridge to cross the gap, researchers report today in Scientific Reports. The team documented 52 crossings of a group of eight gibbons, with most walking along one rope while holding on to the second rope for support,which the scientists named"handrail". The gibbons also shimmied underneath the ropes using all arms and legs to the opposite side.

Conservationists previously built artificial bridges to help other species such as the Bornean orangutan and the Javan slow loris. But this is the first example of the rare Hainan gibbon using them. The rope bridges could be a short-term solution to reconnect disjointed(脱节的)habitats, the researchers argue.

Researchers at a university in Hungary say there is truth to what many dog owners always believed. Dogs do understand what humans say.

The researchers made images of the brains of 13 dogs using a machine that records brain activity. The dogs were trained to lie down in the machine for seven minutes. During that time, they listened through headphones to their trainers’ voices.

Dog owners may think the news is not surprising. But scientists are impressed. Brian Hare is a professor at Duke University. He called one of the findings a “shocker.”

The brain imaging showed dogs processed words using the left side of their brains, just as humans do. They use the right side of their brains to understand tone and pitch (音调). The study showed dogs understand words and how they are said. Meaningful words said in a neutral (中性的) way did not have the same effect as the same words said in an encouraging way.

Attila Andics was the lead researcher on the project. “Dog brains care about both what we say and how we say it,” he said. Researchers say they think dogs are tuned in to what people say because dogs have lived with people for a long time. Andics said he thinks other animals probably can understand human language like dogs do. But those animals are not very interested in what humans have to say.

People reacted to the story on Facebook and Twitter. They said they always knew their pets could understand them. And they were happy to see scientific support for what they experienced every day. One reader from Virginia said she thought her dog could probably read her mind, too. Someone in California joked that he always knew his dog ignored him. And Greg Matos in Boston called the study “fascinating!”