Nature
Komodo dragons kill with venom, not just dirty saliva
For decades, biologists believed Komodo dragons killed prey through septic bacteria festering in their mouths. A 2009 study using MRI scans found instead that they have genuine venom glands in their lower jaws, secreting compounds that cause rapid blood loss and shock. The bacteria theory, it turned out, had never actually been tested.
— Bryan Fry et al., A Central Role for Venom in Predation by Varanus komodoensis — PNAS, 2009