Like humans, being overweight can have consequences for our pet's health, both short term and long term. Studies have shown that overweight dogs do not live as long. 【小题1】 . There is a risk of killing your pet with kindness.

Using special calorie-controlled foods from the vet is usually the most effective way of losing weight and well worth considering. 【小题2】 . Many vets run weight control clinics providing regular check-ups. They are often free of charge, and help to ensure that the diet is working at the correct rate.

With calorie-controlled food from the vet, you will be advised how much to feed daily. Many dry diets come with calibrated scoops (带刻度的勺子) but it is easy to overfill these. You can reduce hunger by feeding two or three times a day, so long as you don't go above the daily recommended amount. 【小题3】

Make a record of everything—including table scraps (剩饭) and treats—that your dog eats for a few days. This is often valuable in highlighting "extra". A dog that does not seem to eat much dog food probably still has an appetite for sausages!

Increasing exercise alone is not enough, although it is helpful. Start gradually, and be careful with how much you exercise elderly pets. 【小题5】 . Consult your vet right away if you notice your dog is limping or struggling with exercise. Try to take your dog out at least twice a day and increase the activity level at home as well.

Papastamatiou’s team studied gray reef sharks living in the waters off Palmyra Atoll, a sunken island ringed by reefs, in the central Pacific Ocean between the Hawaiian Islands and Fiji. They attached small location transmitters to 41 sharks, which allowed them to track the animals movements around the reef. After tracking the sharks for four years, the researchers found that the same groups of sharks frequently returned to the same parts of the reef over and over again. They also found that some of the groups stuck together longer than previous studies have observed.

The sharks might be motivated to stay together, Papastamatiou says, because it makes hunting for food easier, “If we hang out together and I see something, then you can come and try and take advantage of that,” he says. “And alternatively, if you see something, then I can try and take advantage of that.”

He emphasizes that the sharks don’t hunt together but says that as long as the group isn’t too large —which would raise competition and conflict—socializing appears to benefit the sharks. And that may be one of the factors that led to sociality in the species.

David Shiffman, who studies shark ecology and conservation at Arizona State University, says he was surprised to learn the sharks stuck together for so long. “I mean, I don’t have a lot of friends I do that with,” he jokes.

Sharks are amazing creatures, Shiffman says. In addition to knowing where to grab a bite by watching their friends, he says, some species of sharks can also learn to solve simple puzzles, just by watching other sharks solve them. Given their intelligence and social abilities, he says perhaps it’s time to drop prejudices about sharks. “It turns out that they are a lot smarter than other people think, and they have more complex social behaviors and more complex abilities to process their environment and learn and change,” Shiffman says.

Terns (燕鸥) may change their flight plans based on a sense of coming typhoons, escaping the influence of the storms but still benefiting from feeding opportunities.

Researchers examined information recorded on six terns from Okinawa, Japan, to learn more about the birds’ migrations (迁移) over many years. The terns flew across part of the Philippine Sea’s “typhoon highway” to get to the islands of Borneo and Sulawesi and varied their leaving times—often obviously waiting to leave until a large typhoon was about to cross their projected path.

“They seem to be able to predict (预测) it,” says Jean Baptiste Thiebot, a post doctoral fellow at the National Institute of Polar Research in Japan and lead author of the new study, which was published in June in Marine Biology. The study offers few clues about how terns might do this, but other research suggests some migrating birds notice infrasonic (次声的) weather signals or observe changing clouds.

The terns Thiebot studied typically avoided the typhoons themselves. But these storms can churn (剧烈搅动) food to the ocean surface, so the immediate results may help the hungry travelers. “They might actually use the typhoon to know when to leave for their migrations each year”, Thiebot says. In the unusually quiet 2017 season, with no sign of a strong typhoon, the birds started their journeys later and flew without stops. Thiebot would like to see this pattern confirmed in a larger study. He also worries that increasing typhoon frequency could affect birds’ prediction accuracy (准确), possibly getting them caught in dangerous weather.

Robert Gill, a retired research wildlife biologist, says that although the study’s sample (标本) size is small, it adds to scientists’ overall understanding of migration. “They are able to predict better than the best weather forecasters we have, ” Gill says, “but they’ve also had tens of thousands, if not millions of years to hone that skill.”