Tuesday, 11 April 2006

A land of hobbits, giant rats and miniature elephants?

Ever wondered what it would be like to be stranded on a deserted island?

What if that island was a lost island of pony-sized elephants, gigantic lizards and even miniature humans? Sound far-fetched? Whilst the idea may be fanciful, scientists think they may have discovered such a place.

The island is called Flores, and is east of Java in Indonesia. A team of Australian and Indonesian paleoanthropologists and archaeologists were looking on Flores for evidence that the Homo sapiens species of humans – the species that we all are – migrated down through Asia and into Australia about 50 000 years ago.

What they found was truly astounding.

They found the remains of at least seven individuals of some type of human, but a type that looks nothing like us. These humans were only about one meter tall, weighed only 25 kg and had brains that were four times smaller than our own.

Scientists now call them Homo floresiensis, on account of where they were discovered, although they are more commonly, and perhaps cruelly, known as Hobbits, after the little human-like species from The Lord of the Rings.

What was even more surprising was that their remains suggested that they may have survived as recently as 12 000 years ago – which means that some of the stories passed down by the local people in the area about seeing little people could possibly be true! Even an editor of the reputable science magazine Nature has suggested that it is not beyond the realms of possibility that one day we may find a human-like species like this still alive and well somewhere in an uncharted part of the world. It is even more likely that, as Homo sapiens and the hobbits were living in the same part of the world at the same time back then, they probably came face to face.
There is currently debate about how to classify these hobbits. It is not sure yet whether they descended from Homo erectus – the same species from which we Homo sapiens descended – or whether they could even be an off-shoot of modern humans – they did have quite sophisticated tools, and although their brains are small, they are big for their size.

It is thought that Homo erectus, a tall not-quite ape, not quite homo-sapiens creature, travelled out of Africa, colonised Asia and then stopped. There’s never been evidence that they travelled over water – simply because they weren’t smart enough. Is this evidence that they did? Or is this evidence that these hobbits are more like us than we think?

What seems clear though is that the reason this species is so small is because of the conditions in which it lived on the island. When they came to the island, and its unsure how that happened at the moment, they would have found a small island with limited resources. As generations passed, they evolved to get smaller and smaller, as in this way they would require less food to survive. Also, having a smaller body in the hot and humid conditions meant that was easier to cool down and less heat was made within the body when they moved around.

Some scientists think that this is an example of island dwarfing, which is a biological phenomenon by which the size of an animal isolated on an island shrinks dramatically over generations. It is a form of natural selection in which a smaller size provides a survival advantage.

But these hobbits were not the only species on the island that were a little strangely shaped. Dwarf elephants were also found on the island and were probably hunted by groups of their hominid counterparts. These animals, called Stegodons, were smaller than modern water buffaloes and also suffered island dwarfing.

Not every species on Flores is small though. In contrast, Flores is still home to a giant rat, which has a head and body size of about 45 cm, and a tail length of up to 70 cm, which means that they can stretch over 1 m! The island is also home to the Komodo dragon, a giant carnivorous lizard that can be as long as 3 m and weigh around 70 kg. If its initial bite doesn’t kill its prey, the over 50 different strains of bacteria in its teeth will. This prey includes pigs and even water buffalo. It might have been able to stay huge on the island, unlike the elephants, because these elephants, and perhaps even our hobbit friends, were the perfect meal size for them.

But whilst the giant rats and dragons survive to this day, the mini humans and elephants do not. Scientists think that they fell victim to a volcano eruption about 12 000 years ago. But could these strange and wonderful species exist somewhere else in the world? Be careful next time you’re shipwrecked and wash up ashore on a deserted island. A race of three-foot high humans who hunt elephants that only come up to your waist, and eat rats as big as dogs may await you. And be careful of the dragons with deadly bacteria-laced saliva. Who ever said science was dull?!

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