Watch your dog’s left eyebrow. That’s how they say they’re glad to see you.

Doctor Dolittle… well, not exactly. But The Telegraph reads dogs’ faces to see if they’re happy to see you:

Animal behaviour experts have found the animals’ emotions are betrayed by specific facial movements that can reveal whether your dog really is pleased to see you.

Using high-speed cameras, the researchers tracked the changes in the faces of dogs in the moments they were reunited with their owners or when meeting a stranger for the first time.

They found that the dogs tended to move their left eyebrow upwards around half a second after seeing their owner.

When the animals were introduced to someone they had never met before, they moved their left ear back slightly.

Dr Miho Nagasawa, from the department of animal science at Azabu University in Sagamihara, Japan, said: “It is difficult to explain this difference in movement between the ears and eyebrows.

“Dogs’ ears are prominent features used to convey emotional expression, therefore our results suggest that dogs were more cautious toward unfamiliar people.

“In contrast, eyebrow movement might indicate a visible response where by dogs attempted to look at their owners more intently.”

Also, there’s video of dogs with happy faces covered in electronic sensors at the link.