Which animals are smart? Your answer may be dogs or elephants. Now one more animal can be added to the list: the sheep.
Scientists said that sheep could be trained to recognize (辨认) familiar (熟悉的) human faces, the BBC reported.
Before testing, scientists let the sheep take a look at the pictures of four famous people, including former (先前的) US President Barack Obama and British actress Emma Watson. Then the sheep went into a room with two computer screens. One screen showed a famous person and the second screen showed a random (随机的) person. The sheep usually walked toward the screen with the famous person.
After discovering the animals' ability to recognize famous people, scientists gave them a new task. They wanted to see whether the farm animals could correctly recognize the same people from different directions. The animals were still able to recognize them, though they were a bit slower to recognize the pictures than before.
Finally, the researchers wanted to know if the sheep could recognize their trainers from a photo. Photos of their trainers were shown on screens with some unfamiliar faces. They weren't given any training, but the sheep could recognize their trainers.
The results show that the animals' face-recognition abilities are similar to those of monkeys and humans.
The researchers said it might be interesting in the future to find out whether sheep could recognize different expressions on people's faces.
