Many people wonder if geckos are a type of lizard or an entirely different creature. Geckos are indeed a type of lizard, belonging to the infraorder Gekkota and primarily the family Gekkonidae. Understanding their relationship requires exploring the broader category of lizards and then focusing on the unique adaptations that define geckos within that group.
The Broad World of Lizards
Lizards are a vast and diverse group of reptiles, encompassing over 7,000 species found across all continents except Antarctica. They belong to the order Squamata, which also includes snakes.
Lizards generally exhibit common characteristics such as being ectothermic, meaning their body temperature is regulated by their external environment. Their bodies are covered in overlapping scales made of keratin, which provides protection and helps reduce water loss. Most lizards have four limbs, a distinct head, and a tail, though some species are legless. They also possess movable eyelids and external ear openings, distinguishing them from snakes. Lizards display a wide range of sizes, from a few centimeters to the three-meter Komodo dragon, inhabiting diverse environments from arid deserts to lush rainforests.
Geckos: A Distinct Family Within Lizards
Geckos are a type of lizard, belonging to the infraorder Gekkota and primarily the family Gekkonidae. With over 1,500 species, geckos represent one of the most diverse groups within the lizard world. They are widely distributed across warm climates globally, thriving in various habitats including forests, deserts, and human dwellings.
Geckos are typically small to medium-sized, with soft skin and often vibrant coloration, though drab grays and browns are also common. Many species are active at night, adapting to darkness with exceptional night vision. Unlike most other lizards, geckos are notably vocal, using a variety of sounds such as chirps, clicks, and barks for communication. These sounds can serve purposes like warning off rivals or attracting mates.
Key Characteristics That Set Geckos Apart
A key feature distinguishing many geckos is their specialized toe pads, enabling them to climb and adhere to nearly any surface, including smooth vertical walls and ceilings. These pads are covered in microscopic lamellae, further divided into millions of tiny hair-like setae. The tips of these setae, known as spatulae, create a large contact area, allowing strong adhesion through van der Waals forces. This adhesive system enables their climbing abilities.
Another distinctive trait for most gecko species is the absence of movable eyelids. Instead, their eyes are covered by a transparent, protective membrane called a brille or spectacle. To keep this membrane clean and moist, geckos frequently use their long tongues to lick their eyeballs. Many geckos also possess the ability to voluntarily shed their tails, a defense mechanism known as autotomy, which distracts predators and allows the gecko to escape. The lost tail can often regenerate over time.