Ancient archaeological sites are also often ancient paleontological sites, too. Animal bones found there may have been brought and deposited there by non-human predators.

The search for the earliest human chefs and meat eaters depends on accurately recognizing the marks on animal bones left by humans and their tools. That means differentiating between the marks of stone tools and human teeth and those left by predators like coyotes, hyenas or wolves -- animals that likely shadowed human settlements, waiting to carry off food waste left by early hunter-gatherers.

To improve the ability of archaeologists to recognize the tooth marks of ancient human carnivores, researchers with the University of the Basque Country recruited volunteers to eat bone-in lamb cuts.

The volunteers gnawed on 90 lamb bones, including phalanges, radii and scapulae. Using only their hands and teeth, volunteers ate raw, roasted and boiled lamb.

After the feasting, scientists studied the bones under a magnifying glass. The researchers found more than half of the bones had marks from chewing that could be differentiated from bones that had been chewed by animals.

Scientists detailed their results in the Journal of Archaeological Science.

Men left more marks than women eaters, but researchers couldn't differentiate between the signatures of male and female eaters. How the meat was prepared also affected the strength and abundance of marks.

"The teeth marks tend to appear more regularly in the roasted or boiled specimens," researchers wrote, "while the damage on the tips, edges and crushing tends to be more usual in the bones eaten raw."

Though recognizing human teeth marks several thousand years later won't be easy, scientists say their latest analysis can be combined with previous studies of stone tool markings to identify animal bones manipulated by early humans.

"It allows us to find out more about human beings in the past and the origin of our modern behavior, about the way we process foods, cooking them or not, and about our way of eating," researcher Antonio Romero concluded in a news release.