Amphibians of the order Anura, which includes both frogs and toads, are frequently mistaken for one another due to their similar overall body plan. Both groups are tailless, carnivorous, and rely on an aquatic environment for reproduction. While all toads are technically a type of frog (belonging to the family Bufonidae), specific anatomical features distinguish them from “true frogs.” These distinctions extend into their internal structure, with the most significant difference found inside their mouths, influencing how each animal secures and consumes its prey.
The Presence of Teeth
The most direct difference in oral structure lies in dentition, as most frogs possess teeth while true toads do not. Frogs typically have two distinct sets of teeth, neither of which is used for chewing or grinding food. The primary set, known as maxillary teeth, forms a fine ridge of tiny, cone-shaped projections along the rim of the upper jaw.
The second type of dentition, the vomerine teeth, are even smaller and are located on the roof of the mouth near the internal nostrils. Both the maxillary and vomerine teeth function solely to hold struggling prey securely in place until the frog can swallow it whole. These teeth are constantly replaced throughout the frog’s life, a condition known as polyphyodonty.
True toads (family Bufonidae) are entirely toothless in their adult stage. The absence of these structures means toads must rely exclusively on the power of their tongue and the crushing force of their jaws to secure a meal. The minute size of the teeth in frogs means they are not easily seen without close inspection, contributing to the misconception that no frogs have teeth.
External Physical Distinctions
Beyond the mouth, the most recognizable differences are found in external appearance and body structure. Frogs typically have smooth, moist skin that often appears slimy, which is necessary for cutaneous respiration (breathing through the skin). Their bodies are slender and streamlined, supported by long, powerful hind legs adapted for leaping and swimming.
Toads, in contrast, possess thicker, drier skin that is bumpy or warty, which helps them retain moisture and thrive in drier, more terrestrial habitats. Their body shape is stockier and more squat, with shorter legs suited for walking or short hops. A defining feature of true toads is the presence of prominent parotoid glands behind their eyes, which secrete a toxic, milky substance as a defense mechanism.
How They Capture Prey
Both frogs and toads are ambush predators that employ a highly specialized, sticky, projectile tongue to capture food. The tongue is attached to the front of the lower jaw, allowing it to be rapidly flipped out and projected at the target. The tongue’s surface is viscoelastic, and the saliva is a non-Newtonian fluid that thins upon impact and thickens upon retraction, creating exceptional adhesion.
Once prey is captured, the presence of teeth in frogs helps maintain a secure grip, especially on larger, more active insects or small vertebrates. Toads must use a different mechanism to dislodge the meal from their sticky tongue. They use a complex action involving a rigid piece of cartilage called the hyoid to scrape the food off the tongue and push it into the esophagus. This reliance on the tongue and scraping motion often limits toads to consuming smaller, less vigorous prey like worms and insects.