The Komodo dragon sounds invented: a lizard up to three meters long with bony armor under its skin, iron-tipped teeth, a sprint of 20 kilometers per hour, and females that can reproduce without a mate. This episode works through the biology behind each claim and finds the facts stranger than the folklore. It starts with a surprise about origins. Fossils from Queensland dating back roughly 3.8 million years show the pride of Indonesia actually evolved in Australia, then island hopped north when sea levels were lower and was stranded when the oceans rose.

The biggest correction concerns how the dragon kills. For decades the accepted story was a filthy mouth full of septic bacteria. In fact dragons clean their mouths carefully after eating, and the real weapons are deep lacerations plus true venom from glands in the lower jaw. The old theory came from watching water buffalo, an introduced animal that flees into stagnant, contaminated ponds with open wounds. The episode closes on a species listed as endangered, with fewer than 3,500 left in the wild.

• Western science did not document the dragon until 1910, when rumors of a giant land crocodile reached a Dutch colonial administrator.
• Thousands of bony plates called osteoderms form armor that only develops with age, because the main threat to an adult dragon is another adult dragon.
• Zoologist Joan Beauchamp Procter disproved the idea that dragons are deaf in the 1920s by training one at the London Zoo to respond to her voice.
• Females can lay viable eggs without a male through parthenogenesis, and because of their ZW chromosome system every hatchling produced this way is male.
• A peptide from dragon blood plasma known as VK25 has been shown in the lab to promote wound healing and kill multi-drug resistant pathogens.