In a startling discovery, researchers have found that more lizard families than assumed till now are venomous, including several species that are popular pets.
The researchers, writing in the journal Nature (published online on Nov. 16), revealed that the symptoms like pain and swelling from lizard bites, which were previously attributed to the bacteria that thrive on bits of meat left between their teeth from their scavenging diet, were actually from the venom, a finding that could have important implications for medical research.
According to Dr Bryan Fry, University of Melbourne, lead author of the research, the venom is the perfect knockout punch by monitor lizards to their prey like small mammals and lizards. It stops blood clotting, rapidly drops blood pressure and heightens the feeling of bite pain.
They assume that lizard venom may have gone unnoticed for so long because it is not fatal, and yet, it may help lizards catch prey.
The researchers isolated crotamine, the classic venom of rattlesnakes whose bite can be fatal to humans, in the eastern bearded dragon, a popular pet. However, the bearded dragon's delivery system is primitive and it is present in such small amounts it would not harm a human.
Until now, only two families of reptiles were known to have venom systems, i.e., the advanced snakes and Helodermatid lizards. However, this study demonstrates there are venom toxins in two more lizard families: monitor lizards, such as the Komodo dragon, and iguana such as the bearded dragon and green iguana, but their toxin secreting glands are smaller than those of snakes.
The study effectively doubles the number of potentially venomous reptile species to 4,600 from 2,300.
Snake toxins are widely used in medicines to treat epilepsy, haemophilia, high blood pressure and thrombosis.
It is speculated that the lizard venom may prove even more useful. For some reason, the molecules in lizard venom are much smaller than those in snakes, and are thus, less likely to cause allergic reactions.
The researchers assert that the newly discovered lizard venom toxins and their molecules present an enormous uncharted resource for drug design and development.