Kingdom - Animalia

Phylum - Chordata

Class - Reptilia

Orders in Illinois - Squamata and Testudinata

"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)

Herpetology is the study of amphibians and reptiles. The two groups are included under a single discipline because historically, they were considered "lower forms" and not worthy of detailed investigation.

Although they share general similarities in appearance, there are important differences between the class Amphibia and the class Reptilia. In fact, reptiles are more closely related to birds and mammals than they are to amphibians!



  • are vertebrates (have a backbone)
  • have scaly waterproof skin
  • have eggs protected by a thick shell
  • are less dependent on water


  • are vertebrates (have a backbone)
  • have permeable skin
  • have permeable egg membranes
  • are constrained to moist habitats


Currently recognized are over 6,500 extant species of reptiles in 50 families in 4 orders.

The four extant orders of reptiles are: