If you had wandered near Azraq, Jordan, you would have helped archaeologists to find a huge trove of stone tools still containing some traces of animal residue. While a few of these items are part of the paleolithic menu that you know about, you would find many of them quite surprising.

Humans of the Middle Pleistocene Age, about 126,000 years ago, were actually capable of adapting and also using a number of animals, such as cattle, horses, duck, and even rhinoceros, shows a study.

Even though tools began to be used from 2.5 million years ago, a research team headed by April Nowell from the University of Victoria was able to trace the exact animals the scientists were hunting down. The Azraq tools showed evidence of the most ancient protein residue. Prior to this study, the oldest animal residue identified on the stone tools was dated to 11,500 years ago.

"It is huge," noted Nowell. "I think that's why we were so, so excited about this and there are bits and pieces of other evidence of the long-term survivability of organics that are starting to appear."

The team of members from US and Jordan universities dug out 10,000 stone tools on the spot of the arid desert. In the Middle Pleistocene age, about hundreds of thousands of years back, this was the wetlands spot. It was the island in which proto-humans before humans in Africa arrived.

Scientists examined the 7,000 tools, including scrapers, flakes, projectile points, and hand axes. Even as 17 tools showed some hints of protein residue, including blood and other animal products, the origin of the residue, sourced in the tiny fissures and crevasses, were confirmed when animal antibodies were matched.

It seems obvious that horses, wild cattle, duck, and rhinoceros were part of the human prey, although how the humans handled these animals then is not clear. 

"What this tells us about their lives and complex strategies for survival, such as the highly variable techniques for prey exploitation, as well as predator avoidance and protection of carcasses for food, significantly diverges from what we might expect from this extinct species," noted Nowell.

The study was published in the Journal of Archaeological Science.