Lizards are a diverse group of reptiles. Almost every lizard possesses teeth, making dentition a defining feature of this vast suborder, Squamata, with the exception of a few specialized groups like turtles and tortoises. The structure and function of these teeth vary dramatically across species, reflecting their specialized diets and behaviors. The fundamental difference lies in how they are physically anchored to the jawbone itself.
How Lizard Teeth Are Attached
The anatomical method by which a lizard’s tooth attaches to its jawbone determines both its strength and its potential for replacement. The two primary types of attachment found among lizards are pleurodonty and acrodonty. Pleurodont teeth are fixed to the inner side of the jawbone, attaching along the bone’s outer wall. This arrangement is common in species such as iguanas, monitor lizards, and geckos, providing a relatively strong attachment to the bone.
Acrodont teeth, by contrast, are fused directly to the top edge of the jawbone, sitting superficially on the rim. Lizards like chameleons, bearded dragons, and uromastyces exhibit this type of dentition. Because they are cemented to the bone’s surface, acrodont teeth are more prone to wear and fracture during feeding. A third type, thecodonty, where teeth are set deep within sockets like in mammals and crocodilians, is extremely rare among lizards.
The Role of Teeth in Lizard Diet
The shape and structure of a lizard’s teeth are directly adapted to its specific ecological niche and feeding habits. The most ancient and common form is simple, conical, or peg-like teeth, which are perfectly suited for grasping and holding small, terrestrial invertebrates. These sharp, pointed teeth function primarily for prehension, or seizing prey, rather than for extensive chewing.
Herbivorous species, such as iguanas, developed complex teeth with multiple cusps, or tips, similar in form to the grinding teeth of early mammals. These multi-cusped teeth allow for the effective shearing and processing of tough plant material. Specialized mollusc-eaters, like the caiman lizard, possess extremely broad, flattened pleurodont teeth in the rear of the jaw, uniquely adapted for crushing the hard shells of snails and clams.
Teeth also serve functions beyond feeding. Venom delivery is a dental specialization, as seen in the Gila monster, which uses grooved teeth in the lower jaw to channel venom into its prey. Additionally, teeth are used for defense against predators and during mating rituals, where some males grip a female’s head or neck during copulation.
Continuous Tooth Renewal
For many lizard species, the loss of a tooth is only a temporary inconvenience due to a biological process known as polyphyodonty, or lifelong tooth replacement. This continuous renewal is characteristic of lizards with pleurodont dentition, where a new replacement tooth develops underneath or beside the old one. Once the new tooth is ready, the old one is shed, and the replacement moves into its functional position, a cycle that can occur every few months.
Acrodont lizards, however, do not share this capability, being instead monophyodont, meaning they generally do not replace their teeth once they are mature. For these species, such as the bearded dragon, tooth wear is permanent, and the biting surface of the jawbone itself eventually takes over the work of the lost or worn teeth.