Oh, yeah...they can definitely chomp down pretty hard. If you get a 6 footer or better latched on to you, he can do some serious damage. There is also the distinct possibility of very serious bacterial infections. One species of Monitor Lizard, the Komodo Monitor or Komodo Dragon (Varanus komodoensis) actually kills larger prey in this manner. It is not a venomous lizard (the Gila Monster and Beaded Lizard are the only venomous lizards), but it's bite is fatal because of the bacteria in it's saliva. It will bite something like a deer or water buffalo and then follow it sometimes for several days until it dies from the infection. The bite is frequently fatal in humans too because the bacteria are so virulent and the infection progresses so rapidly that antibiotics are ineffective.