Six thousand years ago, the Egyptian wilderness was a very different place. Lions ruled, zebras gathered in large herds, giraffes foraged from tall trees. We know that, in part, thanks to drawings on the walls of ancient Egyptian tombs. Can ancient art help us better understand modern Egyptian wildlife?
Fossilized remains of plants and animals weave an intricate story of life and death in prehistoric Egypt, but conditions have to be just so for biological matter to become a fossil. To fill in the gaps, Santa Fe Institute researcher Justin Yeakel turned to ancient art and architecture. After all, early humans in the area were painting plants and animals well before the pyramids were even an idea. Art betrays the presence of hippos, giraffes, elephants, hartebeests, and foxes. A 5000 year old drawing shows ostriches and ibex. The nearly 2000 year old tomb of Khnumhotep II contains a scene (above) in which a curious cheetah sniffs a wary hedgehog.
Yeakel combined these sorts findings into an ecological timeline already begun by palentological remains, which is described in PNAS. The most important signal for ecosystem health, they found, was the relative abundance of predators to prey. Writing for Science, Jessica Ruvinsky explains:
The researchers explored whether some of the ecological networks were more vulnerable than others. For each mammal community of the last 6000 years, they assembled possible predator-prey networks based on the body size of the animals (a cheetah is more likely to hunt a hedgehog than vice versa)—a system that correctly predicts who eats whom up to 74% of the time in modern African systems. Then they modeled the stability of each ecological network: How likely is a small change to cause a complete collapse?
Over the last 6000 years, Yeakel found that there were five majors shifts in the make-up and diversity of mammals in the Egyptian ecosystem. Three of them were associated with broad environmental changes; namely, the Nile River Valley dried up. A another was associated with the population growth and rapid industrialization of the modern era. By looking at how ancient ecosystems responded to climate-related and anthropogenic changes, perhaps researchers can better understand how our current world will change as the planet becomes warmer.
The most ancient and species-rich ecosystems were resilient. But the networks became less and less stable through time. With each extinction, the mammals that depended on that species become more vulnerable to collapse themselves. The loss of the wild boar, the white antelope, and the leopard in the last 150 years caused the most precipitous drop in stability yet. "As you lose diversity, you lose redundancy in the system, and the importance of each organism becomes magnified," Yeakel says.
An adult male golden jackal, a close relative of coyotes and wolves. (Steve Garvie/Wikimedia Commons)
Today, there are just eight large mammals left in Egypt, including the charismatic striped hyenas and mythical golden jackals. If Yeakel's timeline yields any predictive power, then today's Egyptian mammal assemblage is at greater risk than any time in the last 12,000 years.
Header image via Australian Centre for Egyptology/Ancient Cultures Research Centre, Macquarie University, Sydney