Scientists are still on the track of why humans yawn, and to add further interest, there are now many studies on which animals yawn and why they do so. Anyone who has ever owned a fish, a reptile, a cat or a dog, or even a rat, a bat, or a ferret, may have noticed they also yawn. In fact, most animals yawn, but it’s probably not because they’re bored or sleepy.
Some interesting studies have been done on the reasons behind yawning. For instance, it’s thought that some primates, and possibly cats and dogs, may yawn as a sign of dominance. Observation of dog and primate behavior has shown that alpha males and alpha females tend to yawn more frequently than do their beta counterparts. This may actually be considered aggressive in certain species, since it is a chance to display lots of pointy teeth. People who wonder whether their dog or cat respects them might think about counting how often they yawn when in their presence. The owner may not be the alpha dog or cat if the animal yawns frequently.
Scientists have also suggested that certain animals open their mouths wide as a way to cool down. This may be particularly true when reptiles yawn. With most reptiles relying on ambient temperature to maintain their body temperature, yawning might be a means for promoting rapid cool down. This may also work for animals that don’t sweat, like pigs and dogs. Exposing the mouth and tonsils to the outside air may cool down the head, even if only slightly.
Researchers have also discovered that, when animals yawn, this may have a contagious effect on other animals of their species. Sharks have been described in this manner, especially when they travel in large groups. A single shark yawning can set off the reaction in the whole community, which can be pretty impressive, or slightly frightening to people close to a bunch of sharks with open mouths. Chimpanzees have been observed exercising contagious yawns too, but it’s still unclear why they do it, just as researchers are not entirely sure why humans are prone to yawn at the sight of other humans doing it.
Many insects do not yawn because their breathing mechanism is very different from that of other animals. Instead of having a central oxygen collection device — the lungs — most insects absorb oxygen from every cell in their body, which then is dissolved into fluid to carry to all the body’s tissues.
Typically, people will find that most animals yawn, and it's easy to find some pretty impressive photos online. It’s something that most members of the animal kingdom have in common, even if researchers can’t figure out exactly why they do it.