Today, the stereotypical image of eastern Africa features immense stretches of grasslands, dotted by herds of huge herbivores, chewing their way across the plains. It seems like a timeless scene, the world’s last glimpse of what it was like when megafauna spanned the globe.

In actuality, these wide grasslands are an extremely recent feature in the region’s history. There isn’t solid evidence of animals consuming C4 plants until a scanty 10 million years ago (mya), and grasslands did not become widespread until the late Pliocene and Pleistocene. This recent birth of what is now a dominant feature of the landscape brings to mind many important questions. Specifically, after C4 plants started to become a food source in the Oligocene, how long did it take different herbivore species to adapt to eating this new type of greenery? Which species were early adopters, and which made the most complete shift from C3 to C4 plants? The process of adapting to a new resource–the relatively young C4 plants–had profound effects on community ecology of eastern Africa, as it provided new ways for large herd animals to both exploit new food sources and partition resources in order to facilitate coexistence and/or higher densities.