Dogs' Facial Movements Linked to Conveying Certain Emotions

Animal behavior researchers have determined that specific facial movements in dogs convey certain emotions, such as whether your canine companion is happy to see you.

Miho Nagasawa, from the department of animal science at Azabu University in Sagamihara, Japan, and her colleagues filmed 12 dogs using high speed cameras to record the animals' faces when their owner or a stranger was revealed from behind a curtain. Colored tags were placed on the dogs' face so that the camera could precisely track the movement of the dogs' facial features, and a partition was in place in between the dogs and the people behind the curtains to control for any factor of smell.

The researchers found that dogs raise their left eyebrow about half a second after seeing their owner, but moved their left ear when introduced to a stranger. Dogs moved the opposite ear when introduced to an item they did not like, such as toenail clippers.

"It is difficult to explain this difference in movement between the ears and eyebrows," said Nagasawa, according to The Telegraph.

"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."

Nagasawa and her colleagues observed that dogs moved their eyebrows upwards whenever they were introduced to a person, but did so far more, particularly on the left side, when that person was their owner.

"Ownership is a significant social factor for dogs. This suggests that human-dog bonding relationships have a biological basis," Nagasawa said.

"Canids are highly social and communicate using an abundant array of facial expressions. These communication methods might play an important role in their communication with humans."

Nagasawa and her colleagues' research is published in the journal Behavioural Processes.