Long before the burly bonobo or the even brawnier gorilla, there lived a very strange ape. So strange, in fact, it weighed the same as a newborn human.
While rooting around the dusty sediment of the Tugen Hills in Kenya, anthropologists from Yale University and Stony Brook University managed to pluck out a tiny fossilized tooth, just a few millimeters in diameter (pictured below). Now, 14 years after this discovery in 2004, they have just published their research on the tooth, revealing a newly identified extinct species of ape – Simiolus minutus – which weighed under 3.5 kilograms (7.7 pounds).
Today, the family tree of apes includes the great apes – us, gorillas, bonobos, orangutans, and chimps – and the lesser apes – gibbons. However, they were once a rich and diverse branch of primates. As reported in the December issue of the Journal of Human Evolution, it’s believed that the miniature ape lived around 12.5 million years ago in the Miocene epoch, a hugely important time in the world of primates.
Around the start of this epoch, just under 25 million years ago, apes evolved and quickly became an extremely diverse group. However, within the last 10 million years, apes were faced with a dramatic slash in species diversity. As you can see today, there's only a handful of ape species around. Why? Well, the researchers are hoping that this bizarre little ape could help to explain.

As a major clue, its teeny tooth shows evidence of leaf-eating, which scientists call folivory. Unfortunately for S. minutus, the earliest colobine monkeys were also fine-tuning this adaptation at the time, putting them in direct competition with each other. By the looks of how things turned out, the monkeys came out on top.
“One thing this shows us is that some apes were leaning toward folivory at just the time when monkeys were evolving their uniquely effective adaptations for it,” Professor James Rossie, of Stony Brook University's Department of Anthropology, said in a statement.
“Under those circumstances, I’m not surprised that this is the last you see of these small apes. We’ve previously found the earliest colobine monkeys at these sites, and now we have an ape that looks like it would have been in direct competition with them for food.”
In other words, “They brought a knife to a gunfight and then found out the knife was a plastic picnic knife,” Rossie told The New York Times.
On the other end of the scale, the largest ape that ever lived was Gigantopithecus, perhaps standing as tall as 3 meters (9.8 feet). Since it only went extinct around 100,000 years ago, it’s likely that it co-existed with humans.