Life-sized drawing shows sloth that was as big as a van

Imagine the scene; you look up to see a shaggy-haired beast as large as an elephant, with foot-long claws and arms dragging to the ground, running towards you on its hind legs.

Imagine the scene; you look up to see a shaggy-haired beast as large as an elephant, with foot-long claws and arms dragging to the ground, running towards you on its hind legs.

Fortunately, few people ever faced the sight of a charging Megatherium - a giant ground sloth existing in South America during the Pleistocene era (between 1.8 million and 11,000 years ago) - as only a short time after humans came into existence, the species died out.

But visitors to London's Natural History Museum can, today, get a glimpse at a close-to-life size drawing of the Ice Age mammal, as part of the Museum's Big Draw celebrations.

Measuring 2.46 by 5.7m - larger than a Transit van - the 14 pieces which make up George Scharf's 1842 work, based upon fossils destroyed during the Second World War, will be reassembled and displayed for the first time. The drawing was always known to be in the museum's collection, but until recently curators did not realise how large it was.

Nor did they know for certain that the creature reared up to its full height to run on two legs: anatomists had mis- instructed the artist, and told him to draw it on all four. The founder of the Natural History Museum, Richard Owen, suspected the error, and installed a cast skeleton on its back legs. Palaeontologists now know from fossilised footprints that he was right.

The herbivore, whose name means "giant beast", is thought not to have had any pre-human predators due to its sheer size and a chainmail skin to put the rhino to shame.

"It's strange they survived all the climactic change of the Ice Age, but disappeared when humans appeared," says Andy Currant, curator of Ice Age mammals. "Man either hunted them or destroyed their habitat." Looking at its size, he added: "Possibly deliberately."