YOKOHAMA (Kyodo) Dogs can tell if someone is smiling or not, a task that is difficult for monkeys and other smart animals, a recent survey by animal experts based in Sagamihara, Kanagawa Prefecture, has found.

The group, led by Miho Nagasawa, a special associate professor at Azabu University, showed five dogs aged 8 months to 6 years two photos of their owners, one smiling, the other not.

The group trained the dogs to press their nose against the smiling photo by rewarding them with food for the right choice. The five dogs were eventually able to choose the smiling photo with an average accuracy rate of 82 percent, the group said.

The accuracy rate fell slightly when the dogs saw photos of strangers. The average rate was 78 percent for someone of of the same sex as the owner, and 62 percent for someone of the other sex, the scholars said.

"This time we haven't shown whether dogs can realize the meaning of a smile. But the possibility is high that they can learn (to tell if the owner is smiling) by seeing the owners' reactions," Nagasawa said.