Many people encounter lizards and geckos and often wonder if these creatures are one and the same, or if there are distinct differences between them. This common question stems from their similar appearances and shared habitats. Understanding their relationship requires exploring their broader classifications and unique characteristics.
Lizards A Broad Group
Lizards represent a vast and diverse group of reptiles, scientifically classified under the order Squamata, which also includes snakes. Within Squamata, lizards primarily fall into the suborder Lacertilia, also known as Sauria. This expansive group encompasses over 7,000 species, inhabiting nearly every terrestrial environment on Earth, from deserts to rainforests.
General characteristics of lizards include being cold-blooded, meaning their body temperature is regulated by their external environment. They are covered in scales, which provide protection and reduce water loss. Most lizards possess four limbs, a tail, and external ear openings, along with movable eyelids. Their diets vary widely, ranging from insects and plants to smaller vertebrates.
Geckos A Unique Family
Geckos are a specific type of lizard, belonging to the infraorder Gekkota, which contains several families, most notably Gekkonidae. While all geckos are lizards, not all lizards are geckos. Geckos are one of the most species-rich groups of lizards, with over 1,500 species identified worldwide.
These small to medium-sized reptiles are found across every continent except Antarctica, thriving in warm climates. Their habitats are diverse, ranging from deserts and forests to human habitations. Geckos typically measure between 1.6 to 60 centimeters (0.6 to 23.6 inches) in length, including their tails.
Key Distinctions
One of the most recognizable features distinguishing many geckos from other lizards is their specialized toe pads. These pads are covered in millions of microscopic hair-like structures called setae, which are further divided into even smaller nano-sized spatulae. These structures create a strong adhesive force through van der Waals forces, allowing geckos to cling to and climb smooth, vertical surfaces, and even ceilings. This adaptation is not universal among all gecko species, but it is widespread.
Another notable difference is related to their eyes. Most geckos lack eyelids; instead, their eyeballs are covered by a transparent membrane called a brille. Since they cannot blink, these geckos typically lick their eyes with their long tongues to keep them clean and moist. A few gecko species, belonging to the Eublepharidae family, are an exception and do possess movable eyelids.
Geckos are unique among lizards for their vocalizations. Unlike many lizards that are mostly silent, geckos communicate using a variety of chirps, clicks, barks, and squeaks. These sounds serve different purposes, such as attracting mates, defending territory, and warning of danger. Many gecko species are also primarily nocturnal, possessing excellent night vision that is significantly more sensitive to light than human eyes.