3 . Race walking shares many fitness benefits with running, research shows, while most likely contributing to fewer injuries. It does, however, have its own problem.

Race walkers are conditioned athletes. The longest track and field event at the Summer Olympics is the 50-kilometer race walk, which is about five miles longer than the marathon. But the sport’s rules require that a race walker’s knees stay straight through most of the leg swing and one foot remain in contact (接触) with the ground at all times. It’s this strange form that makes race walking such an attractive activity, however, says Jaclyn Norberg, an assistant professor of exercise science at Salem State University in Salem, Mass.

Like running, race walking is physically demanding, she says, According to most calculations, race walkers moving at a pace of six miles per hour would burn about 800 calories(卡路里) per hour, which is approximately twice as many as they would burn walking, although fewer than running, which would probably burn about 1,000 or more calories per hour.

However, race walking does not pound the body as much as running does, Dr. Norberg says. According to her research, runners hit the ground with as much as four times their body weight per step, while race walkers, who do not leave the ground, create only about 1.4 times their body weight with each step.

As a result, she says, some of the injuries associated with running, such as runner’s knee, are uncommon among race walkers. But the sport’s strange form does place considerable stress on the ankles and hips, so people with a history of such injuries might want to be cautious in adopting the sport. In fact, anyone wishing to try race walking should probably first consult a coach or experienced racer to learn proper technique, she says. It takes some practice.

6 . Researchers say they have translated the meaning of gestures that wild chimpanzees (黑猩猩) use to communicate. They say wild chimps communicate 19 specific messages to one another with a “vocabulary” of 66 gestures. The scientists discovered this by following and filming groups of chimps in Uganda, and examining more than 5,000 incidents of these meaningful exchanges.

Dr Catherine Hobaiter, who led the research, said that this was the only form of intentional communication to be recorded in the animal kingdom. Only humans and chimps, she said, had a system of communication where they deliberately sent a message to another group member.

“That’s what’s so amazing about chimp gestures,” she said. “They’re the only thing that looks like human language in that respect.”

Although previous research has shown that apes and monkeys can understand complex information from another animal’s call, the animals do not appear to use their voices intentionally to communicate messages. This was a significant difference between calls and gestures, Dr Hobaiter said.

Chimps will check to see if they have the attention of the animal with which they wish to communicate. In one case, a mother presents her foot to her crying baby, signaling: “Climb on me.” The youngster immediately jumps on to its mothers back and they travel off together. “The big message from this study is that there is another species (物种) out there. that is meaningful in its communication, so that’s not unique to humans,” said Dr Hobaiter.

Dr Susanne Shultz, an evolutionary biologist from the University of Manchester, said the study was praiseworthy in seeking to enrich our knowledge of the evolution of human language. But, she added, the results were “a little disappointing”.

“The vagueness of the gesture meanings suggests either that the chimps have little to communicate, or we are still missing a lot of the information contained in their gestures and actions,” she said. “Moreover, the meanings seem to not go beyond what other animal convey with non-verbal communication. So, it seems the gulf remains. ”

7 . According to a recent study in the Journal of Consumer Research, both the size and consumption habits of our eating companions can influence our food intake. And contrary to existing research that says you should avoid eating with heavier people who order large portions(份), it's the beanpoles with big appetites you really need to avoid.

To test the effect of social influence on eating habits, the researchers conducted two experiments. In the first, 95 undergraduate women were individually invited into a lab to ostensibly(表面上)participate in a study about movie viewership. Before the film began, each woman was asked to help herself to a snack. An actor hired by the researchers grabbed her food first. In her natural state, the actor weighed 105 pounds. But in half the cases she wore a specially designed fat suit which increased her weight to 180 pounds.

Both the fat and thin versions of the actor took a large amount of food. The participants followed suit, taking more food than they normally would have. However, they took significantly more when the actor was thin.

For the second test, in one case the thin actor took two pieces of candy from the snack bowls. In the other case, she took 30 pieces. The results were similar to the first test: the participants followed suit but took significantly more candy when the thin actor took 30 pieces.

The tests show that the social environment is extremely influential when we're making decisions. If this fellow participant is going to eat more, so will I. Call it the “I’ll have what she's having” effect. However, we'll adjust the influence. If an overweight person is having a large portion, I'll hold back a bit because I see the results of his eating habits. But if a thin person eats a lot, I'll follow suit. If he can eat much and keep slim, why can't I?

8 . We are the products of evolution, and not just evolution that occurred billions of years ago. As scientists look deeper into our genes (基因), they are finding examples of human evolution in just the past few thousand years. People in Ethiopian highlands have adapted to living at high altitudes. Cattle -raising people in East Africa and northern Europe have gained a mutation (突变) that helps them digest milk as adults.

On Thursday in an article published in Cell, a team of researchers reported a new kind of adaptation - not to air or to food, but to the ocean. A group of sea-dwelling people in Southeast Asia have evolved into better divers. The Bajau, as these people are known, number in the hundreds of thousands in Indonesia, Malaysia and the Philippines. They have traditionally lived on houseboats; in recent times, they’ve also built houses on stilts (支柱) in coastal waters. “They are simply a stranger to the land,” said Redney C. Jubilado, a University of Hawaii researcher who studies the Bajau.

Dr. Jubilado first met the Bajau while growing up on Samal Island in the Philippines. They made a living as divers, spearfishing or harvesting shellfish. “We were so amazed that they could stay underwater much longer than us local islanders,” Dr. Jubilado said. “I could see them actually walking under the sea.”

In2015, Melissa Ilardo, then a graduate student in genetics at the University of Copenhagen, heard about the Bajau. She wondered if centuries of diving could have led to the evolution of physical characteristics that made the task easier for them. “it seemed like the perfect chance for natural selection to act on a population,” said Dr. Ilardo. She also said there were likely a number of other genes that help the Bajau dive.

10 . When you were trying to figure out what to buy for the environmentalist on your holiday list, fur probably didn’t cross your mind. But some ecologists and fashion (时装)enthusiasts are trying to bring back the market for fur made from nutria(海狸鼠).

Unusual fashion shows in New Orleans and Brooklyn have showcased nutria fur made into clothes in different styles. “It sounds crazy to talk about guilt-free fur-unless you understand that the nutria are destroying vast wetlands every year”, says Cree McCree, project director of Righteous Fur.

Scientists in Louisiana were so concerned that they decided to pay hunters $5 a tail. Some of the fur ends up in the fashion shows like the one in Brooklyn last month.

Nutria were brought there from Argentina by fur farmers and let go into the wild. “The ecosystem down there can’t handle this non-native species(物种).It’s destroying the environment. It’s them or us.” says Michael Massimi, an expert in this field.

The fur trade kept nutria in check for decades，but when the market for nutria collapsed in the late 1980s，the cat-sized animals multiplied like crazy.

Biologist Edmond Mouton runs the nutria control program for Louisiana. He says it’s not easy to convince people that nutria fur is green, but he has no doubt about it. Hunters bring in more than 300,000 nutria tails a year, so part of Mouton’s job these days is trying to promote fur.

Then there’s Righteous Fur and its unusual fashion. Model Paige Morgan says，”To give people a guilt-free option that they can wear without someone throwing paint on them-I think that’s going to be a massive thing, at least here in New York.” Designer Jennifer Anderson admits it took her a while to come around to the opinion that using nutria fur for her creations is morally acceptable. She is trying to come up with a label to attach to nutria fashions to show it is eco-friendly.