Toads, generally belonging to the family Bufonidae, are amphibians often confused with frogs, though all toads are technically frogs within the order Anura. The term “toad” describes species sharing distinct physical characteristics and behaviors. Understanding these features is the first step in accurately identifying these squat-bodied creatures. Identification moves from general visual cues to specific anatomical markers and environmental indicators.
Visual Identification: Distinguishing Toads from Frogs
The most immediate difference between a toad and a typical frog is the appearance of the skin. A toad’s skin is characteristically dry, thick, and rough, giving it a warty, bumpy texture that aids in camouflage and water retention in drier environments. In contrast, most frogs possess smooth, moist, and often slimy skin, which is important for cutaneous respiration—breathing through the skin.
Toads tend to have a squat, robust, and broad body, appearing thickset and heavy. Frogs, conversely, are usually more slender and streamlined, built for agility and movement.
A toad’s hind legs are noticeably shorter and sturdier than a frog’s. These short legs are adapted for walking, crawling, or making short, awkward hops, as toads spend most of their time on land. Frogs have long, powerful hind legs specialized for long-distance leaping and swimming, allowing them to cover much greater distances in a single bound. Toads generally lack teeth entirely, whereas most frogs possess small vomerine teeth on the roof of their mouth.
Anatomical Markers: Parotoid Glands and Cranial Crests
Beyond visual comparison, true toads possess specific anatomical structures that serve as definitive identification markers. The most prominent of these are the parotoid glands, which are large, raised, and often kidney-shaped swellings located on the back of the head, behind the eyes and ear drums. These glands contain bufotoxins, a milky, alkaloid secretion that acts as a neurotoxin to deter predators.
This defensive secretion is discharged when the toad is stressed or attacked. While touching a toad will not cause warts, the toxins can irritate a person’s eyes or mucous membranes, so washing hands thoroughly after handling is a necessary precaution, particularly to protect household pets.
Cranial crests are bony ridges found above or between the eyes in many toad species, such as those in the genus Anaxyrus. These crests are formed from dermal bone and become more pronounced as the toad matures. The specific shape, size, and connection point of these crests relative to the parotoid glands can be a precise tool for distinguishing between different species of toads.
Behavioral and Habitat Clues
Observation of movement and preferred environment offers valuable identification clues. Toads are terrestrial, spending their lives away from permanent bodies of water. They are often encountered in gardens, woodlands, and fields, preferring drier, loose soil where they can burrow for cover.
Their movement reflects their terrestrial lifestyle, characterized by a sluggish walk or a series of short, deliberate hops. Toads are nocturnal, active at night or during warm, humid conditions and rain. During the day, they seek refuge under logs, stones, or leaf litter to prevent dehydration.
While they live on land, toads must return to water to breed. The eggs are laid in long, gelatinous strands, often wrapped around aquatic vegetation, which is distinct from the clumped egg masses deposited by most frogs. Finding an amphibian far from water is a strong indication it is a toad.
Applying Identification to Common Species
Common North American species provide specific examples for identification. The American Toad (Anaxyrus americanus) is often identified by its warty skin, where the dark spots on its back typically contain only one or two warts. The cranial crests on the American Toad are either completely separated from the parotoid glands or connected only by a short spur.
A closely related species, the Fowler’s Toad (Anaxyrus fowleri), presents a subtle contrast; its dark spots usually contain three or more warts, and its cranial crests touch or run directly into the large parotoid glands. Another example is the Southern Toad (Anaxyrus terrestris), which is unique for often having extremely tall cranial crests that terminate in prominent, bony knobs, sometimes giving the toad a “horned” appearance. In contrast, the much larger Cane Toad (Rhinella marina), an invasive species in many regions, is recognized by its massive size, reaching up to 9 inches, and its unusually large, triangular parotoid glands.