Why Do We Yawn?

Person yawning.You may be copying someone else when you yawn and/or regulating body temperature. Those are the two main reasons scientists believe are responsible for the common yawn.

A yawn is a deep intake of breath that is accompanied by a widening of the mouth and stretching of ear drums. It is followed by a large exhalation of air. People often stretch their arms and other body parts while yawning.

Yawning to Regulate Temperature

Frequent yawning has been observed in a ‘thermal window’ when it is cold/hot enough outside for the yawned air to cool/warm the body down, but not so cold/hot that the intake of air would be harmful. People in warm places tend to yawn more in winter months while people in cold places yawn more in summer months.

Yawning to regulate body and brain temperature is particularly helpful, and often observed, just before people start a strenuous or stressful experience. These include a gym workout, sporting contest or just before public speaking. Yawning cools the brain just a little, which can help it work more efficiently.

Yawning in Empathy

Contagious yawning has often been observed where one person’s yawn appears to be transmitted to others who witnessed it. The same phenomenon has also been observed among numerous animal species, including primates and dogs.

Group yawning may be partly explained by everyone being in the same place and having a similar experience. But there appears to be a strong psychological component as well. The reasons are not fully understood but are conjectured to reflect our tendencies to mimic and empathise with others.

Yawning When Tired

So why do we yawn when we’re feeling tired? This is most likely linked to temperature regulation. Sleep deprivation and tiredness are both known to make the brain hotter. So yawning may help  keep our brains working closer to an optimal temperature.


Why Do Dogs Eat Grass?

Papillon dog resting on and possibly eating grass.It is quite normal for dogs to eat grass. Wolves and other wild dogs are known to regularly eat plant matter. For domestic dogs, grass is the most common plant they see. It appears tasty to them at certain times and depending on what else is in their diet.

Top Reasons Why Dogs Eat Grass

While eating grass comes naturally to dogs, there is no definitive reason why they do it. They seem predisposed to doing it and it probably benefits their health. Some possible reasons why your pet dog may be eating grass are:

  • To increase dietary fibre
  • To gain some nutrients that it may be low on
  • To alter the mix of enzymes and bacteria in its gut
  • Just to see what it tastes like / experiment.

Dogs have often been seen vomiting shortly after consuming grass. It has been hypothesised that, in such cases, dogs may eat grass to gain relief from some kind of stomach upset.

Is Eating Grass a Problem?

Eating grass should not normally be considered a behavioural issue that needs correcting. But it may be dangerous if the grass is coated with fertiliser, pesticides or herbicides.

You can protect a grass eating dog by not using toxic products on your lawn or garden beds. In public, watch for signs or warnings that chemicals have been used on the grass. You can also provide alternative sources of vegetable matter by growing a grass or herb garden and by feeding your dog more vegetables.