This large family is well known across most of the planet thanks mostly to its largest genus, Bufo, the true toads, which has around 200 described species distributed globally except for Madagascar and most of the Australasian region, although the cane toad (Bufo marinus) has recently been introduced to much of the latter. This mostly terrestrial family has adapted to live in nearly every imaginable habitat. The twenty-three or so genera are fairly uniform in structure, mostly squat and heavy-bodied with a warty skin texture. A large paratoid gland is often present behind each eye. These organs secrete milky toxins that defend the animal against predators. The pupils of all species are horizontally oval, and males have a structure called a Bidder's organ, a vestigal ovary which can become functional if the testes are damaged.

Across most of Eastern North America the American toad is a common amphibian that is frequently encountered in a variety of habitats. Spending the daylight hours in hiding, it emerges at night to actively gorge itself on invertebrates. On spring evenings the lovely trill of the males can be heard around water bodies. The responding females attach their eggs in long strings to submerged plants. The newly hatched tadpoles are black, swim in shoals and develop into toadlets after a few weeks.