One thing is clear, animals do it too. Cats, rats, birds and even frogs have been caught yawning. Many carnivores yawn, but herbivores rarely do so . The rhino, for example, is an excellent yawner and even tropical fish yawn.
It is not very clear why we yawn or what are the causes that trigger it. In order to find out, some scientists began to observe people several years ago. They found that the time of day when you yawn the most is the first hour after waking up and the second hour immediately before going to sleep.
On the other hand, there are animals that do it because an important moment of the day or something that requires their full attention is approaching. Thus, lions and baboons yawn when it is time to eat and a tropical fish known as the Siamese fighter almost never yawns alone, but just show it another specimen of the same species so that its yawning rate is multiplied by 300, and if he is going to go into battle, he yawns even more.
However, among humans it seems that we yawn when we lack stimulation, when we are bored. Although this is not always true. When we are in stressful situations we yawn a lot, and students tend to yawn before an exam, just like athletes before starting a test.
And if all this is difficult to explain, its contagious aspect is even more so. Even thinking about yawning is enough to start doing it like crazy.
