We used to brag that Arizona’s native Gila Monster was one of only two living species of venomous lizards, the other being its close cousin, the Beaded Lizard That was before an international team of researchers led by Dr. Bryan Fry of the University of Melbourne, Australia discovered that the Komodo Dragon and some of its relatives produce venom, debunking the longstanding notion that virulent, septic bacteria living in the dragon’s nasty, toothy maw were the source of its toxic bite.
Now a team of researchers led by Chinese paleontologist Enpu Gong have found evidence that Sinornithosaurus, a small feathered dinosaur, also used chemical weapons. The fossils show grooved teeth similar to those found in the Gila Monster, Beaded Lizard, and a number of rear-fanged venomous snakes, as well as a recess in the jaw that may have housed the venom gland. Venomous dinosaurs were imagined in Jurassic Park (remember the “spitters”?), but this may be the first hard evidence for such creatures.
Gong and his colleagues suggest that Sinornithosaurus was a specialized bird hunter whose venom helped to subdue its active, mobile prey quickly and safely (for the predator, that is). Likewise for the Komodo Dragon. Thanks to venom components that inhibit coagulation and lower blood pressure, even a relatively minor bite results in rapid blood loss and unconsciousness. The dragon can bite a deer or pig, let it go to avoid injury from flailing hooves, and then track the animal while it waits for the venom to do its work. In many venomous snakes, the venom not only kills the prey but begins the digestion process as well.
Gila Monsters live mainly on the eggs of birds and reptiles, so immobilizing and/or digesting their prey isn’t much of an issue. Why be venomous, then? The answer probably lies in these lizards’ relatively small size and couch-potato physique. Such plump, slow-moving reptiles would be an easy meal for large birds of prey, Coyotes, Bobcats, etc. if not for a powerful bite made even more painful by a dose of venom. Human victims of Gila Monster bites describe them as excruciating. Like coral snakes, Monarch butterflies, and a host of other creatures with chemical defenses, The monster sends a warning to would-be predators with its retro pink-and-black color scheme and bold patterns: Attack me and you’ll be sorry!