The team says the humans who ate the elephant belonged to Homo heidelbergensis. The ancient humans had brains about three-quarters the size of our own and walked fully upright.
H. heidelbergensis is thought to have been the ancestor of the Neandertals, which became extinct about 30,000 years ago, after modern humans colonized Europe.
"We don't think [H. heidelbergensis] had clothing, and they didn't use fire, so they would have eaten the elephant raw," Wenban-Smith said.
"They probably ate bits like the brain, trunk, tongue, and the marrow."
The elephant's missing jawbone could have been smashed by the early humans to get at the marrow inside, the team says.
"They would have broken the bone up and then sucked on it," Wenban-Smith said.
He says the team can't be sure how the hunters killed the animal, but a wooden spear was found alongside another Stone Age elephant in Germany.
"There's evidence in Britain at Boxgrove [also in southern England] that a horse was hunted and killed with a [wooden] spear at the same period as the elephant site," he added.
The team also discovered a big pile of flints about 65 feet (20 meters) from the animal, on the shore of the ancient lake, which may represent a more permanent tool-making site.
"The location had a stream and a good view over the local landscape, so it may have been where the hunter-gatherers mostly lived," Wenban-Smith said.
"It's a site where they made lots of tools."
The straight-tusked elephant was identified by Simon Parfitt of the Natural History Museum in London. He says the forest-dwelling species died out in England more than 100,000 years ago at the beginning of the last ice age.
Other animals found nearby included two extinct species of volea small rodent resembling a mousethat were used to date the site.
Previous studies show that one of the species, a pine vole, has been extinct in England for the last 400,000 years. The other, a type of water vole, wasn't present before 500,000 years ago.
The site also yielded teeth from mice and pollen traces from tree species that are still present in Britain, suggesting that the climate back then was similar to today's.
"The landscape would have been much more forested, of course, with occasional open patches around river plains where there would have been a high density of grazing animals," Wenban-Smith said.
Besides the elephant skeleton the team unearthed the remains of rhinos, buffalo, deer, and wild horses, all mammals that early humans preyed on.
"We know these people didn't dwell in fixed structures, and they primarily lived by hunting animals and gathering plant foods at certain seasons," Wenban-Smith said.
He says stone artifacts from the site may provide further clues about how early humans lived, such as how many of them were in a group.
For example, the team recovered six larger stones known as cores, from which flint tools used for butchering the elephant were chipped.
"If each person had one core, that's at least six people," Wenban-Smith said.
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