Drop a lizard’s tail and it buys you an escape
More than seven thousand lizard species span every continent but Antarctica. Many answer predation with a radical trick: they self-amputate the tail, leaving a thrashing decoy while the body flees. Add sticky toe pads, projectile tongues, and—even in some monitors—venom, and “lizard” becomes less a type than a toolkit.
Squamate reptiles called lizards (usually excluding snakes, and sometimes worm lizards) range from the 13.5-millimetre nano-chameleon and tiny Jaragua dwarf gecko to the three-metre Komodo dragon. Most walk with a side-to-side quadrupedal gait; some sprint on hind legs, glide on rib membranes like Draco for up to sixty metres, or run across water like the basilisk. Keratin scales shed in pieces, not a snake’s single stocking, and help desert species hold water. Legless lineages reinvented a serpentine body by convergent evolution—one reason cladists note that “lizard” is paraphyletic unless snakes count as specialised lizards.
Senses and weapons vary wildly. Geckos lick lidless eyes clean; chameleons fire sticky tongues and can aim eyes independently; monitors flick forked tongues to a vomeronasal organ. Until 2006 only the Gila monster and Mexican beaded lizard were thought venomous, yet several monitors, including Komodo dragons, secrete potent salivary venoms—lace monitor toxins can drop blood pressure and block clotting. Genes tied to snake toxin families appear in many lizards’ salivary glands, hinting at a Toxicofera ancestry roughly two hundred million years old, though many of those genes are ordinary housekeeping sequences.
Reproduction is equally inventive. Most species lay eggs; about twenty percent give live birth with placenta-like support, common among anguimorphs. Some whiptails are all-female parthenogens, and a captive Komodo female produced eggs after more than two years without males. Temperature during incubation can skew sex ratios—cooler nests more females, warmer more males—while other species use XY or ZW chromosomes. From alpine meadows to Galápagos coasts, the group thrives by matching that biological versatility to almost every habitat humans know.
Source: Lizard
