The tooth enamel of the leopard, spotted hyena, and Megantereon drew a match, indicating that the individual specimens studied, at least, may have feasted on hominids. The findings were published in the Journal of Human Evolution.
To most paleontologists, the leopard and spotted hyena have long been obvious predators of hominids; even today, the modern descendants of these flesh-eating mammals have been known to attack and devour humans.
Megantereon, however, is a surprise to some scientists.
Bob Brain, a paleontologist who pioneered the investigation into hominid predators in his book The Hunters or the Hunted?, doesn't think that Megantereon fits the hominid killer profile. He believes their canine teeth would have caused little damage to a hominid skeleton.
"Its long canines were too delicate and probably only effective in slicing up larger prey," Brain said.
In his book, Brain suggested that Dino felis, the false saber-toothed cat, was a specialist primate killer, picking off hominids and baboons and then dragging them back to its cave lair.
Lee-Thorp's research, on the other hand, seems to clear the false saber-toothed cat; its carbon isotope ratios suggest that it concentrated on grazing animals, filling a niche that modern lions occupy today.
Larry D. Martin, curator of vertebrate paleontology at the University of Kansas Natural History Museum, has no problem seeing Megantereon as a hominid killer.
"Although Megantereon has large teeth, it is fairly small bodied and I doubt that it took larger prey than does the modern lion, which is a serious potential threat to modern hominids. I have no doubts that Megantereon would take a hominid whenever one might become available," he said.
Professor Phillip Tobias, emeritus professor of Anatomy and Human Biology at the University of the Witwatersrand, believes Lee-Thorp's study has greatly enhanced scientific understanding of the diets of early hominids, apes, and that of some of the large carnivores.
"For a long time this has been the object of much study; (Raymond) Dart first claimed that ape men hunted all other mammals, then C.K. (Bob) Brain determined through a series of brilliant analyses that it was primates that were the hunted and not the hunters. Now Lee-Thorp and her colleagues' research appears to provide proof that ape men were being hunted," Tobias says.
There is not enough isotopic evidence yet to absolutely convict any of these predators, and Lee-Thorp is looking forward to collecting more evidence at other dig sites.
"Our study was limited to only a few specimens. It could be a case of where those individuals tested ate one thing while their peers concentrated on something else. Only further testing will tell," she said.
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