Monkeys seem to have a way with numbers.

A team of researchers trained three Rhesus monkeys to associate 26 clearly different symbols consisting of numbers and selective letters with 0­25 drops of water or juice as a reward. The researchers then tested how the monkeys combined — or added — the symbols to get the reward.

Here’s how Harvard Medical School scientist Margaret Livingstone, who led the team, described the experiment: In their cages the monkeys were provided with touch screens. On one part of the screen, a symbol would appear, and on the other side two symbols inside a circle were shown. For example, the number 7 would flash on one side of the screen and the other end would have 9 and 8. If the monkeys touched the left side of the screen they would be rewarded with seven drops of water or juice; if they went for the circle, they would be rewarded with the sum of the numbers — 17 in this example.

After more than a year, the two bears returned to the wild. “Not a lot of agencies have the funding to do this kind of work. We hope to leave the state of Washington with better bear management than when we arrived,” said Rich Beausoleil, WDFW biologist. “We’ve found our public here in Washington appreciate that we go the extra miles and give these orphaned bears a second shot at life.”

If you ever get the impression that your dog can “tell” whether you look content or annoyed, you may be onto something. Dogs may indeed be able to distinguish between happy and angry human faces, according to a new study.

Researchers trained a group of 11 dogs to distinguish between images (图像) of the same person making either a happy or an angry face. During the training stage, each dog was shown only the upper half or the lower half of the person’s face. The researchers then tested the dogs’ ability to distinguish between human facial expressions by showing them the other half of the person’s face or images totally different from the ones used in training. The researchers found that the dogs were able to pick the angry or happy face by touching a picture of it with their noses more often than one would expect by random chance.

The study showed the animals had figured out how to apply what they learned about human faces during training to new faces in the testing stage. “We can rule out that the dogs simply distinguish between the pictures bused on a simple cue, such as the sight of teeth, ” said study author Corsin Muller. “Instead, our results suggest that the successful dogs realized that a smiling mouth means the same thing as smiling eyes, and the same rule applies to an angry mouth having the same meaning as angry eyes.”

“With our study, we think we can now confidently conclude that at least some dogs can distinguish human facial expressions,” Muller told Live Science.

At this point, it is not clear why dogs seem to be equipped with the ability to recognize different facial expressions in humans.“To us, the most likely explanation appears to be that the basis lies in their living with humans, which gives them a lot of exposure to human facial expressions, ” and this exposure has provided them with many chances to learn to distinguish between them, Muller said.