Anything crawling or reptilian...as long as it moves around close to the ground and has scales.

Herpetology is the study of amphibians, reptiles or cold-blooded tetrapods. It benefits humanity in the study of the role of reptiles in global ecology, because they are often very sensitive to environmental changes, offering a visible warning to humans that significant changes are taking place. Some toxins and venoms produced by reptiles are useful in human medicine.