a broad family including only nonvenomous snakes, containing about two-thirds of all living species. It includes the bullsnakes, garter snakes, and water snakes as well as many other species.

(Käl' oo br d) Of the 2,700 known species of snakes, 2,200 are classified within this family. Characteristics of these snakes include a loose facial structure, few head scales, and complete lack of a left lung and absence of front fangs that inject venom.