【推荐1】The amount of plastic pollution in the oceans is rapidly increasing. This is problematic, as at least 700 species of sea animals may mistake it for a tasty snack. While we know that some species seem to eat plastic because it looks like jellyfish or some other food source, less research has been carried out into what plastic smells like to marine animals.

But now, a study from the University of North Carolina has found that the coating of algae that naturally builds up on ocean plastics causes the rubbish to give off the scent of food.

The researchers took 15 loggerhead turtles, each around five months old, and placed them in a laboratory tank. They then piped in clean water, clean plastic, turtle food, and plastic that had been immersed in the marine environment for five weeks.

The turtles showed no reaction to the smell of clean water or clean plastic. But when they were exposed to the smell of ocean-soaked plastic 'or turtle food, they exhibited food-seeking behaviors like reaching their noses out of the water or showing increasing activities.

“This finding is the first demonstration that the smell of ocean plastics causes animals to eat them,” said Dr. Kenneth J Lohmann, who took part in the study. "It's common to find loggerhead turtles with their digestive systems fully or partially blocked because they've eaten plastic materials. There are also increasing reports of sea turtles that have become ill and stranded on the beach due to their ingestion of plastic."

According to the researchers, areas of the ocean with dense concentrations of plastic may trick turtles and other animals into thinking that there is an abundant food source. "Once these plastics are in the ocean, we don't have a good way to remove them or prevent them from smelling like food," said Lohmann.

【推荐2】For thousands of years, humans have used names to communicate with one another. We also give names to animals, especially ones we love, such as pets. Until now there has been little evidence of animals naming one another, but a new study suggests that elephants use specific noises to identify other elephants.

A few animals, including parrots and dolphins, have been known to use sounds that are similar to names. Each dolphin invents a signature whistle that is unique to it, and other members of its species communicate with it by simulating this special call. The new study, led by Michael Pardo of Colorado State University, shows that wild African elephants use names in a way that is not just copying sounds and is much closer to the way humans use names.   

For the study, the researchers recorded 625 sounds made by wild African elephants in Kenya that they called "rumbles (隆隆声)”. This is the most common type of call produced by elephants, and it can travel long distances-as far as 3. 7 miles. It takes place at a very low frequency, which means humans can't hear it.

The researchers analyzed the sounds using computers and found that certain rumbles were directed at specific elephants to get their attention They found that all the elephants in the herd used the identical call to get a particular elephant's attention -these calls were not just nicknames used by one of the elephant's friends. Also. unlike the way dolphins communicate. the rumbles were not just imitations of the elephant they were trying to communicate with.

The researchers then played back some of the recorded rumbles to the elephants. They found that elephants responded more to their own name than to other calls. coming toward it more quickly or calling back faster. Cartlin O'Connell-Rodwell, an elephant expert, said, "The study shows that elephants can still keep in touch with one another even across a large area. "She told Live Science, "The rumbles ere magical, which allow them to spread out much further and still have very close tabs（密切关注） on individuals. "

【推荐3】As a volunteer, John Apollos is losing weight - the old-fashioned way - by eating less. Apollos has lowered his daily caloric intake 25% over the past eight months. The fat, not surprisingly, has melted away. But that’s not the real reason Apollos and the other participants in the program are eating only three-quarters of what they used to. The researchers are trying to determine whether restricting food intake can slow the ageing process and extend our life span. “I feel better and lighter and healthier,” says Apollos. “But if it could help you live longer, that would be pretty amazing.”

The idea is counterintuitive: If we eat to live, how can starving ourselves add years to our lives? Yet decades of calorie-restriction studies involving organisms ranging from microscopic yeast to rats have shown just that. Last July a long-term study led by researchers at the University of Wisconsin, found that calorie restriction seemed to extend the lives of humanlike rhesus monkeys (恒河猴) as well. The hungry monkeys suffered from diabetes, heart and brain disease and cancer much less frequently than their well-fed fellows did.

Scientists have suspected that calorie restriction could extend the life span of animals since at least1935, when researchers at Cornell University noticed that severely food-restricted lab rats lived twice as long as normal ones and were healthier. Other investigators began exploring the idea and learned that the secret is not merely a matter of body weight.

One theory is that a state of slight hunger acts as a mild but constant stressor that makes an organism stronger and more resistant to the ills of ageing. Taking in fewer calories also slows metabolism (新陈代谢), and some data indicate that humans with a slower metabolism live longer. But even if these theories are correct, simply defining the mechanism is not the same as identifying the molecular pathways behind it. If researchers could determine those pathways, they might be able to pharmacologically mimic (模仿) the effect of calorie restriction. That could be the ultimate benefit of the CALORIE study. “Calorie restriction is pretty much the only thing out there that we know will not just prevent disease but also extend maximal lifespan,” says Dr. Marc Hellerstein, a nutritionist at the University of California.

【推荐2】Companies in New Zealand are working with American creators of some of Hollywood’s most famous creatures to develop animatronic dolphins that look almost the same with their living counterparts.

A robotic dolphin that can nod an answer to a child might sound unappealing. But as marine parks around the world face increasing pressure to abandon exhibitions featuring real whales and dolphins, the creatures provide an appealing alternative, their creators say.

But with a price tag of about NZ$40m (£ 20.8m) per dolphin, the biggest obstacle for the creators of the animatronic creatures is proving to potential clients that the robotic sea creatures will work out to be cheaper in the long run than the real thing.

Li Wang, a business developer for Edge Innovation, the New Zealand-based company making the case for the robots, said they do cost four times more than normal dolphins but would last longer.

Melanie Langlotz, one of the managers behind the project said, the robotic dolphin can’t be distinguished from the real thing. A test audience had been unable to guess the dolphin was not real, she added.

Animal rights advocates also welcomed the change. They hoped robotic dolphins would replace real ones in marine parks worldwide.

In nature, dolphins swim up to 40 miles a day and live in close family groups, but in captivity they were confined to concrete pools filled with chemically treated water and forced to interact with strangers. In the near future, cutting-edge technology might allow us to experience nature without harming it.