According to new research from the University of Cambridge in England, sheep are able to recognize human faces from photographs. The farm animals, who are social and have large brains, were previously known to be able to recognize one another, as well as familiar humans. However, their ability to recognize human faces from photos alone is novel.

The recent study shows the woolly creatures could be trained to recognize still images of human faces, including those of former President Barack Obama and actress Emma Watson.

Initially, the sheep were trained to approach certain images by being given food rewards. Later, they were able to recognize the images for which they had been rewarded. The sheep could even recognize images of faces shown at an angle, though their ability to do so declined by about 15 percent—the same rate at which a humans ability to perform the same task declines.

“Anyone who has spent time working with sheep will know that they are intelligent, individual animals who are able to recognize their handlers,” said Professor Jenny Morton, who led the Cambridge study. “We’ve shown with our study that sheep have advanced face-recognition abilities, comparable with those of humans and monkeys.”

Recognizing faces is one of the most important social skills for human beings, and some disorders of the brain, including Huntington’s disease, affect this ability. “Sheep are long-lived and have brains that are similar in size and complexity to those of some monkeys. That means they can be useful models to help us understand disorders of the brain, such as Huntington’s disease, which develop over a long time and affect cognitive abilities. Our study gives us another way to monitor how these abilities change,” Morton said.

A curtain call is a series of bows and applause usually held at the end of a live performance.【小题1】Curtain calls can sometimes become encores (再唱，再演的呼声), where extra material is performed at the request of the audience.

【小题2】Ensemble (合唱团) members, dancers and ensemble actors will bow first, featured roles will follow and the stars of the show will bow last. Usually the curtain call is concluded by a company-wide bow, often including recognition to the band. In traditional staging, after the company-wide bow, the stage curtain will be lowered and raised again if applause continues.

The general rule of taking a bow suggests that shorter is better. 【小题3】 These longer curtain calls may include speeches and individual thank-yous. The director or the producer of the event is often invited onstage to share in the final curtain call, and sometimes presented with gifts from the cast.

Normally, when an actor is performing, he/she will avoid talking directly to the audience and acknowledging their presence. Even when they look off-stage, they do not look directly at the audience. Yet, during the curtain call, actors are free to be themselves. 【小题4】.

Nothing ruins a good show like an excessively long curtain call. If the show consists of six or fewer actors, it’s fine for everyone to take an individual bow. But in performance with medium to large casts, the curtain call includes groups of actors based on the size of their role. The group of actors don’t need to run, but they do need to be quick. 【小题5】 Then they’ll make way for the next group of performers.

A slow death is creeping through Earth’s forests. As animals are killed by hunters or forced away by logging, the plants that depend on them to carry their seeds begin to disappear. Over time, trees and other plants may vanish. Climate change is accelerating this process, a new study suggests—and it may eventually harm biodiversity.

Many plants need help to move about the world. About half of all species rely on birds and mammals to eat or carry their fruits and nuts to new places. When these partners disappear, forests and plant communities can struggle to regenerate.

Climate change is making things worse. As temperatures warm and rainfall decreases, plant populations will have to extend their ranges by as much as tens of kilometers per year.

Ecologist Evan Fricke, wanted to know how well plants all across the planet might be able to move to new habitats. He and his colleagues gathered existing data from thousands of studies that looked at how birds and mammals spread seeds, including how far they travel and what percentage of the seeds actually get to grow. They focused on seeds that are dispersed more than 1 kilometer, a distance that is great enough to expand populations and help them recover from disturbances.

The average ability of plants to keep pace with climate change has already declined by 60%, the research found. “That should certainly be ringing alarm bells,” says Fricke, “We’re ‘forcing’ plants to move these great distances, but we’ve also significantly slowed their ability to do so.”

The loss of the ability is greater in temperate (温带) regions according to the research. That’s because these areas have lost many populations and species of large fruit-eating mammals, which can move seeds longer distances. Also, the challenge for plants is greater there, because when climate conditions change in relatively flat landscapes, species must move farther north to keep cool. In contrast, an alpine plant (高山植物) only has to move uphill to get to a cooler climate.

The situation could   get worse.   In   another   analysis, the researchers predicted what might happen if currently threatened and endangered seed-dispersing birds and mammals go extinct. This would reduce a plant’s ability to keep up with climate change by another 15%.

However, some of the damage can be repaired by connecting isolated habitats. That will better allow species to move in response to climate change. Reintroducing large animals to their former ranges could also help, because they can move seeds long distances.

“This is a very loud wake up call for urgent conservation efforts” of fruit-eating and seed-dispersing animals, says ecologist Rodolfo Dirzo. “What’s important,”he says, “is not just preventing extinction, but   keeping populations big enough to help many plants reproduce.”