30. Not All Animals Yawn
If you have spent any time around cats and dogs, you know that they yawn quite a bit. After all, they are social creatures who are exhibiting one of the most primitive of all social behaviors. However, there are plenty of other animals that are also social but do not yawn.
Case in point: insects. They don’t yawn. Ever. But this isn’t because they are psychopaths (even though mosquitoes may be psychopaths). Insects don’t yawn because they don’t have central repositories, aka lungs, for collecting oxygen. However, they are still highly social creatures.