The high humidity combined with the physical exertion of the morning’s film shoot left me exhausted. After lunch, I lay down on one of the wooden benches in the large covered porch of the rangers’ hut in Rinca Island, Indonesia. A loud voice made me jump, “This is no place to sleep.” The ranger ordered, “Get up!”

“What’s the problem?” I asked as I reluctantly sat up.

“Komodo dragons.”

“But… but this hut is on stilts.”

“A couple of months ago, a komodo climbed up one of the stilts and bit a guard’s arm and leg.”

When I first arrived on Rinca, I thought the average 2.5-mt komodos were no more than super-sized water monitor lizards, a species with which I was familiar. The difference is the giants are fearless and powerful.

Like many island creatures, these animals are not shy. Or perhaps they don’t fear humans because they are so large. For creatures used to bringing down deer and water buffalo, I was a pint-sized morsel. In the past 35 years, komodos have killed four humans. Still, even the tall Indians and Europeans on the film crew felt unsafe around these lizards. Armed with sticks, we walked in groups constantly scanning front, back and the sides for komodos lying in ambush. A gigantic, carnivorous, man-eating lizard is the stuff of nightmares.

Komodos were thought to have reached their great size by feasting on 300-kg stegodon elephants that lived on this group of Indonesian islands. Islands have a peculiar way of turning giant species such as stegodonts to pygmies, and smallish species suc has monitor lizards to giants.

However, the tiger-sized elephants went extinct 12,000 years ago, while humans brought pigs from Sulawesi only about 7,000 years ago. The deer and buffalo came even later. In the intervening 5,000 years, komodos managed to survive and maintain their huge sizes by hunting small prey. So did elephants really lead to the evolution of the largest lizard in the world?

In 2009, after studying fossil evidence, a team of archaeologists led by Scott Hocknull of Queensland Museum, Australia, concluded komodos evolved in Australia and colonised islands as far west as Java, Indonesia. Today, this race of giants has disappeared from its Australian homeland, and is relegated to the Indonesian islands of Rinca, Flores, Komodo and the two tiny islands of Gili Montang and Gili Dasami.

Fearless komodos are scary enough. Until 40,000 years ago, lizards twice as large wandered across much of inland Australia. Called megalania (meaning ‘ancient great wanderer’), the biggest ones reached seven mt in length, about 1,940 kg in weight, and lived off rhinoceros-sized marsupials.

Not surprisingly for creatures this size, early Aborigines were also on the menu. There was no tree a man could climb and no hole in the ground he could dig to get away from these monsters. The last Ice Age put an end to the Aborigines’ nightmare.

India had a giant lizard too. In the 19th Century, two vertebrae and a thigh bone were found at an unknown location in the Siwaliks. Estimated to grow up to 3.5 mt, the lizard roamed the area 2.5 million years ago. Not only does it seem to have been rare, fortunately, it lived in a different era from humans.

The same year Hocknull established the Australian origin of komodo dragons, a team of venom experts led by Bryan Grieg Fry of the University of Melbourne added a new dimension. For a long time, it was thought deadly septicemia-causing bacteria festered in the mouths of komodos. Fry said it wasn’t bacteria that disabled prey, but venom seeping from a gland located in the lizards’ lower jaw. The venom disrupted blood coagulation and caused blood pressure to plummet. The quarry went into shock and lost consciousness, to be eaten at leisure by the predators.

Since megalanias are related to komodos and similar venomous lizards, they may have been the largest venomous vertebrates to have ever evolved.

Those poor Aborigines.