The common term “lizard push-up” refers to a specific, rhythmic body movement performed by many lizard species, notably the Anolis lizards, involving vertical body or head movements. This behavior, known scientifically as display behavior or head-bobbing, is a complex form of visual communication. Female lizards perform this action, though their reasons are often distinct from male displays. The “push-up” is not exercise, but a method of conveying information about the lizard’s social status, intent, or readiness to interact.
The Anatomy of a Lizard “Push-Up”
The movement that resembles a calisthenic push-up is a visual signal achieved by rapid flexing of the lizard’s forelimbs and pectoral girdle muscles. When the entire body rises and falls, it is classified as a “push-up” display; a movement limited to the head is a “head-nod.” The purpose of this movement is to create a conspicuous signal easily seen by other lizards. These displays are highly species-specific, acting as a visual code that allows lizards to recognize their own kind through distinct patterns in speed, duration, and amplitude. While male anoles often enhance this show by extending their brightly colored throat fan (dewlap), female anoles rarely deploy this structure.
Male Display: Territorial and Mating Signals
The male lizard display is the most recognized use of the push-up and head-bob, serving two main functions: establishing dominance and initiating courtship. Males use these high-frequency, high-amplitude movements to advertise their presence and defend territories against rivals. A vigorous display signals to an intruder that the territory holder is healthy and prepared to fight, often preventing physical conflict. In a mating context, the male’s energetic head-bobbing and dewlap extension signal his species identity and sexual interest to potential mates. The frequency and vigor of a male’s display can be an honest signal of his physical condition and fitness.
Why Female Lizards Display
Female lizards use the push-up and head-bob display for important, though often less vigorous, social communication. One primary function is signaling sexual receptivity during courtship. When a male approaches, a female may perform a specific head-bob or body posture to indicate that she is accepting of his advances. Conversely, the display can be used for outright rejection or aggression. A quick, sharp head-bob or a series of push-ups can signal to an unwanted male that he should withdraw his attention. Females are also territorial, defending resources such as prime basking spots or foraging areas against rivals, using the push-up as a core part of the aggressive behavioral repertoire.