Why do dogs yawn?

 

Why do dogs yawn?

This morning I noticed both Roxy and Gilbert yawning before they went out for their walk. They had been dressed in their collars and were waiting to leave, not taking their eyes off Barry, alert to every movement.

I know that dogs sometimes yawn to alleviate stress, so if a dog yawns when a small child is fussing around it, it might be a good idea to intervene. Small humans don’t understand dog signals and dogs can only communicate in non-linguistic ways. Because of this, it is never a good idea to leave young children alone with dogs of any size. A dog disciplines its puppies by biting and shaking, but puppies have protective fur, not delicate skin, and will not be harmed. Humans have no such protection and can and will be severely damaged.

I’ve never been bitten in anger, but once was caught by Frodo’s teeth when he was unaware during a seizure. It hurt – a lot – and it bruised badly. He would have been mortified, my Velcro dog.

I looked up other reasons for canine yawning. Tiredness can cause it, but my dogs were anticipating an enjoyable outing. Dogs may yawn to calm themselves or each other, or to indicate submission and that they are not presenting a threat. Roxy and Gilbert know each other very well and do not have to compete for their position in the pack. In any case, they are working Labradors, bred to cooperate with people, and other dogs.

Dogs may also yawn in an attempt to regulate their body temperature, in much the same way as panting. They can also show contentment through yawning when they are being caressed. Sometimes, they will yawn in response to their people yawning. 

None of these causes fitted the situation, so it was clear that they were yawning because they were excited. Now, a few hours later, they are relaxed and sleeping, Roxy spread out in a dog bed and Gilbert keeping my feet warm. I don’t think he will ever grow out of that endearing puppy habit of seeking refuge next to me. 

                 Emerging from the pond, each with their own ball!

Yawning

 

Yawning

There has been relatively little research carried out on the subject of yawning, but it is known that humans yawn about twenty times a day and also that babies in the womb yawn from about 11 weeks’ gestation. Tiredness and boredom are cited as common causes of yawning. (Surely unborn babies aren’t bored? ‘I’m fed up hanging around in here. There’s nothing to do or see. There must be more to life than this.')

A yawn is an involuntary reflex, involving an intake of breath through the mouth and a swift exhalation. In addition to yawning when weary or bored, conversations about yawning can cause participants to yawn. Simply reading the word ‘yawn’ triggers the reflex.

Yawning is contagious, perhaps even more so than smiling, but children are not affected by contagious yawning before the age of four. It is difficult to resist the urge to yawn when others are doing so. Yawns aren’t always silent, either. They are frequently accompanied by sighs or verbalisations like, ‘Oh, dear me’ or perhaps inarticulate grunts or groans. Stretching often plays a part, too.

Gallup, in the journal ‘Evolutionary Psychology’, presented the hypothesis, in 2007, that yawning regulates brain temperature. Taking a lot of air into the lungs through yawning cools the blood that flows to the brain and improves the ability to concentrate.

In 2014, researchers looked at how outdoor temperatures affected the frequency of yawning. When it’s hot, people yawn more. When the temperature drops yawning is less frequent. When it reaches 37° C (98.6°F) which is the average body temperature, yawning is no longer effective in cooling the brain.

However, the hypothesis, though popular, is not proven. For example, it cannot account for mouth-gaping or yawning in cold-blooded animals.

Many animals yawn. Contagious yawning is thought to be an evolutionary behaviour, particularly in pack animals, to induce attention within the group and alertness to danger. The theory is that if an individual yawns, it is indicating to the rest that it is sleepy and therefore less vigilant. The yawn spreads, increasing the overall watchfulness and safety of the pack.

Human yawns are contagious to dogs, but it is not certain that cats are similarly affected.