Pound for pound they are incredibly powerful, says Dr Stephen, the largest lizard in the world measuring up to three metres long (9ft 10ins) and 120kg (265 lbs). And they are strong swimmers so could follow a fleeing human into the sea.
"Generally they attack their prey but don't kill it there and then. They have a poisonous saliva full of different bacteria, about 80 species of bacteria. So in a couple of days septicaemia sets in and the prey dies."
Contrary to some reports they do not spit venom, he says, but their teeth are shark-like and leave a very nasty and poisonous bite. If the wounded prey gets away the dragon can follow a blood trail a couple of miles away.
A kill usually attracts many dragons who feed according to their own hierarchy.
Humans living on the islands within the national park habitat of the dragons have learnt how to adapt to the dangers. Their houses are on stilts.
Although attacks on humans are rare, an eight-year-old German boy was mauled to death there in 2007.
Dr Stephen says a Komodo dragon in the wild would not hesitate to kill and eat a human if they wanted to...
