As everyone knows, smelling is the name of the sensation that emerges as a result of the brain’s evaluation of the electrochemical stimuli produced by chemicals in an environment on certain receptors. The main function of smell is to distinguish chemicals that are difficult/impossible to perceive with other sense organs in an environment. Thanks to our sense of smell, we can distinguish the presence of chemicals that we can never see with our eyes and often cannot feel by touching. The sense of smell plays an important role in many animals. Species such as mice, dogs, sharks are known examples. However, in some animals, the sense of smell lags behind other organs. These animals are also called humans, eagles, etc. Let’s take animals as an example. Of course, animals in this second category also use their sense of smell and sometimes it may be in an important position, but basically other senses such as sight are more important in these organs.