Elephants once roamed forests in the Atlas Mountains of Mediterranean North Africa. Towering tusks and trunks were a commonplace sight for Egyptian pharaohs and ancient Carthaginians. War elephants once even invaded Roman Italy.
Sometime between 2,000 and 1,500 years ago, these elephants vanished.
“Why does it matter?” SFI Fractal Faculty and Roman historian Kyle Harper (University of Oklahoma) wondered. “Beyond the intrinsic value of the species and its contribution to diversity — which alone is something quite valuable and extraordinary — how does losing these animals affect other parts of the ecosystem?”
A working group at SFI on “Megafauna Depletion and Holocene Ecological Networks” addressed this very question, bringing together historical ecologists, conservation biologists, computational modelers, and archaeogeneticists on March 17–19, 2025.
Since the last major ice age, declines in megafauna — animals weighing more than 100 pounds — have directly affected climate change, wildfires, and natural resources. That’s because large animals play a crucial ecosystem role. For example, they remove flammable vegetation, create habitats for other creatures, and contribute methane emissions and carbon storage.
The problem is worldwide. Alpacas and llamas in South America, Atlantic whales, bison on the North American plains: all have dwindled within the last 11,700 years. That’s the period known as the Holocene, “when humans began to dominate Earth’s landscapes with colonization, large-scale agriculture, and eventually industrialization,” says Courtney Hofman, a University of Oklahoma molecular anthropologist who works with Harper tracking archaeological elephant ivory.
Thus, the complex history of megafauna reveals how humanity has reshaped the Earth. “Megafauna are still at high risk today,” says Hofman. “Extending the timeline further back to how some species survived this human-influenced change, and others succumbed, can inform strategies for managing these animals now.”
Hofman and Harper anticipated the working group could develop new tools for predicting ecosystem resilience and preventing megafauna loss. Participants discussed case studies from the later Holocene — a largely unexplored time period for studying animal body size reduction.
“Loss of megafauna is a deep pattern over time,” said Harper in the lead-up to the meeting. “Big animals affect entire systems as consumers, nutrient cyclers, ecosystem engineers. The working group will tackle those complex relationships between animals, plants, and nonliving things that are very hard to understand and model.”