Why is it said that the sense of smell is very important to reptiles?

Like our nostrils, reptiles have nasal passages. The nasal passage is lined with tiny hairs. These hairs can sense very small units of substances that are to be smelled. The nasal passages of most reptiles have an opening into the mouth. An organ called the Jacobson’s organs opens into the nasal passages of snakes and lizards. This organ helps snakes and lizards to smell. The sense of smell is very important to reptiles. The sense of taste is closely related to the sense of smell, but it is not as important as the sense of smell, for reptiles.

Pit vipers, rattle snakes, and pythons have a special organ for sensing heat called the pit organ. The pit organ is located on the sides of the head between the eyes and the nose. The pit organ can sense even tiny changes in temperature. The snake senses the body heat of mammals and birds with the help of its pit organ, and it goes for the kill. A rattle snake can strike accurately at a mouse or a man in total darkness, with the aid of its pit organ.