Australia: The Land Where Time Began

A biography of the Australian continent 

Megalania prisca

This was a giant monitor lizard from the age of megafauna in Australia. It is the largest lizard ever found, and was almost certainly still extant when the first Aboriginal People arrived in Australia about 60,000 years ago. It survived until about 40,000 years ago, so might have been a threat to the first Aboriginal People, and they may have helped it on its way to extinction as an act of self-preservation. The much smaller Komodo Dragons are a danger to humans at the present, being known to have taken children from villages. While crocodiles could have been avoided by avoiding watercourses where they lived, the Megalania roamed the bush so could possibly have been encountered while walking through the bush.

It has been difficult to be certain of the length and mass of M. prisca because of the lack of a near complete fossil material, but enough has been found to estimate an approximate size of this huge goanna. The estimates of its size range from 4.5 m (15 ft) to 7.9 m (26 ft) for the biggest specimens. Ralph Molnar in (2004) estimated a length based on the size of the dorsal vertebrae after he determined a relationship between dorsal vertebrae length and total body length. In his estimates, if it had the build of the Lace Monitor (Varanus varius), with its long tail, it would have been about 7.9 m (26 ft) long. If it was more like the Komodo Dragon, with a shorter tail, it would have been about 7 m (23 ft). If the maximum length was 7 m he estimated that it weigh in at about 1940 kg (4300 lb), with a thinner average of about 320 kg (710 lb). Not all agree with these size estimates (Wroe, 2002). Wroe argues that the body mass has been greatly overestimated. His methods give an estimated average size of about 100 kg, with particularly large individuals getting a bit larger. Wroe also believes scavenging probably provided a large proportion of its food, as with the goanna and the komodo dragon. Johnson (2006) suggests that the fact that so few fossils of Megalania have been found suggest it was not common.

Whoever is correct, it was a very big goanna.

It had serrated, blade-like teeth, a large skull and a heavily built body. Assuming it had similar feeding habits to its present-day relatives, it could have been an opportunistic feeder, being both a hunter and a scavenger. There is disagreement about its hunting method, and how much of its diet would have consisted of carrion. Both the Lace Monitor and the Komodo Dragon scavenge and hunt. The Komodo Dragon is an ambush hunter, lunging at large prey such as deer and clamping its powerful jaws on any part of the animal it can reach. If the animal is too large to bring down immediately it lets go after a while then uses its forked tongue like any other monitor to track the wounded animal until it finds the incapacitated animal. It was believed that it was waiting for the bacteria to take their toll on the prey, travelling through the animal's bloodstream until it collapsed. It is now known that by clamping onto the animal it squeezes its venom glands, the venom trickling down the teeth to the wound where it enters the animal's circulation.

There is controversy about whether it was the top predator of the time or even a main predator, its remains are uncommon in Pleistocene deposits, whereas those of the marsupial lion  (Thylocoleo carnifex) are very common. The fossil remains of large Pleistocene mammals show signs of being butchered by marsupial lions, but none have been found that show signs of having been butchered by Megalania. It seems hard to believe that a reptile so much bigger than a Komodo Dragon, with such flesh-tearing serrated teeth and a large powerful head, and most likely equipped with poison glands, didn't occasionally hunt like a Komodo Dragon. If it was a gentle giant, what did it eat?

There have been claims that some still survive in outback Australia, not everyone believes this.

Large Reptilian Predators

Sources & Further reading

  1. Chris Johnson, Australia's Mammal Extinctions, a 50,000 year history, Cambridge University Press, 2006


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Author: M. H. Monroe
Last Updated 30/09/2011

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