Wolves have a certain undeserved reputation: fierce, dangerous, good for hunting down deer and farmers’ livestock. However, wolves have a softer, more social side, one that has been embraced by a heart-warming new initiative.

In a bid to save some of Europe’s last wolves, scientists have explored the willingness of these supposedly fierce creatures to help others of their kind. Female wolves, the scientists have discovered, make excellent foster parents to wolf cubs that are not their own. The study, published in Zoo Biology, suggests that captive-bred wolf cubs(幼兽) could be placed with wild wolf families, boosting the wild population.

The gray wolf was once the world’s most widely distributed mammal, but it became extinct as a result of widespread habitat destruction and the deliberate killing of wolves suspected of preying on livestock. Fear and hatred of the wolf have since become culturally rooted, fuelled by myths, fables and stories.

       In Scandinavia, the gray wolf is endangered, the remaining population found by just five animals. As a result, European wolves are severely inbred and have little genetic variability（变异性）, making them vulnerable to threats, such as outbreaks of disease that they can’t adapt to quickly. So Inger Scharis and Mats Amundin of Linkoping University, in Sweden, started Europe’s first gray wolf-fostering program. They worked with wolves kept at seven zoos across Scandinavia. Eight wolf cubs between four and six days old were removed from their natural parents and placed with other wolf packs in other zoos. The foster mothers accepted the new cubs placed in their midst.

The welfare of the foster cubs and the wolves’ natural behavior were monitored using a system of surveillance cameras. The foster cubs had a similar growth rate as their step siblings in the recipient litter, as well as their biological siblings in the source litter. The foster cubs had a better overall survival rate, with 73% surviving until 33 weeks, than their biological siblings left behind, of which 63% survived. That rate of survival is similar to that seen in wild wolf cubs. Scientists believe that wolves can recognize their young, but this study suggests they can only do so once cubs are somewhere between three to seven weeks of age.

If captive-bred cubs can be placed with wild-living families, which already have cubs of a similar age, not only will they have a good chance of survival, but they could help dramatically increase the diversity of the wild population, say the researchers. Just like the wild wolves they would join, these foster cubs would need protection from hunting. Their arrival could help preserve the future of one of nature’s most iconic and polarizing animals.

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Nowadays, many people love to travel. It is very common for people to go on a trip at any time.【小题1】 Perhaps, the reason for its present popularity is that more people have come to realize the benefits of traveling.

Traveling provides a good many opportunities for fun, adventure and discovery. When we visit other countries, we gain a better understanding of the people living there. We learn their cultures, history and background. We discover the similarities they have with us. 【小题2】 It is interesting to learn from people with different backgrounds.

Traveling helps to enrich our lives. 【小题3】 When we visit interesting places, we discover and learn many things. We discover new people, surroundings, plants and animals. If we want to make our travel more exciting and challenging, we can plan our own tour and select the specific places we want to visit.

Traveling is refreshing. It is a psychological necessity, especially for people who have stressful jobs.【小题4】 Staying at home during the weekend is not enough to make some people feel relaxed.【小题5】It helps them to handle the stress they experience at work better. After the break , they feel more energetic in their work. For many working adults, regular getaways help them keep their energy and enthusiasm they require for their work. Without these breaks, they may suffer from work burnout.

Gravity signals that race through the ground at the speed of light could help seismologists(地震学家) get a better handle on the size of large, destructive quakes soon after they hit，a study suggests. The tiny changes in Earth’s gravitational field, created when the ground shifts, arrive at earthquake monitoring stations well before earthquake waves.

“The good thing we can do with these signals is have quick information on the magnitude (震级) of the quake,” says Martin Vaillée, a seismologist at the Paris Institute of Earth Physics.

Earthquake equipment in China and South Korea picked up gravity signals immediately after the magnitude-9. 1 Tohoku earthquake that destroyed parts of Japan in 2011. The signals appear as tiny accelerations on earthquake-recording equipment, more than a minute before the seismic waves show up.

“We can look before the earthquake waves arrive,” says Vallée. “If we see nothing, we can say that the quake that made these was maybe large, but not huge. If we see the signals, it means we really have a very big quake. ”

Had seismologists been monitoring for gravity changes, they might have realized sooner just how big the Tohoku earthquake was. A small increase in an earthquake’s magnitude means a large change in the energy released by the quake-and the destruction expected. That information is important for emergency responders as they decide what resources to arrange.

It’ll be a major contribution if gravitational waves can beat down the time needed to know that a big earthquake is big. But much work remains before gravity signals can be considered a reliable tool in the vital minutes after a big quake. A few extra minutes of warning can save lives, particularly in coastal areas where people can flee ahead of an incoming tsunami.