The word Herpetology is derived from the Greek Herpes which means crawling. Living amphibians are salamanders, frogs, and odd ball legless creatures called caecilians. Living reptiles are lizards, snakes, crocodilians, turtles, and a lizard-like creature called the Tuatara. This course focuses on the living groups of amphibians and reptiles and there are about 7,300 species of amphibians and about 10,000 species of reptiles living in the world today.

Amphibians, reptiles, birds and mammals form a branch of the animal family tree called the tetrapods (limbed vertebrates). Mammals and birds each have their own field of study. Mammalogy for mammals and Ornithology for birds. As a field of study, Herpetology is a bit strange because reptiles are more closely related to birds and mammals than they are to amphibians. In biological terms, Herpetology is a polyphyletic field of study. So why don’t we have separate fields for amphibians and reptiles? Linnaeus is why. The father of modern taxonomy, Carolus Linnaeus, lumped amphibians and reptiles into the same class. Interestingly, Linnaeus disliked amphibians and reptiles. Of them he said:
“These foul and loathsome animals are abhorrent because of their cold body, pale color, cartilaginous skeleton, filthy skin, fierce aspect, calculating eye, offensive smell, harsh voice, squalid habitation, and terrible venom; and so their Creator has not exerted his powers to make more of them.”
–Carolus Linnaeus (1758).
Linnaeus’ disdain for amphibians and reptiles is perhaps the reason why he ignored their numerous differences and lumped them together.
Herpetology has another quirk. The reptiles falling under the umbrella of herpetology are the lizards, snakes, rhynchocephalians, turtles, and crocodilians. These are often called non-avian (i.e. non-bird) reptiles. This specification is necessary because the class Reptilia does include birds. Birds (the clade Aves) are reptiles. In fact, crocodilians are more closely related to birds than they are to any other non-avian reptiles. From an evolutionary point of view, it does not make sense to include crocodilians with lizards, snakes, and turtles, but not birds. In biological terms, non-avian reptiles form a paraphyletic group. That is the other quirk of herpetology. In this course though, I will use the term reptiles to refer to non-avian reptiles.
While the collection of taxa studied by herpetologists does not make much sense from an evolutionary point of view, there are reasons to study amphibians and reptiles together. Amphibians share a few traits with reptiles that reptiles do not share with birds and mammals including the way they regulate their body temperature, which, as we will see later, has a profound impact on their ecology and behaviour. Moreover, birds are extremely specialized reptiles with many features absent in non-avian reptiles including sustained flight. Considering their huge diversity (over 10 000 living species) and their high degree of specialization, it makes sense to give birds their own field of study.
Historical and phylogenetic considerations aside, amphibians and reptiles, or “Herps”, are fascinating organisms deserving to be studied. I hope you will find learning about them as enriching as I have.