8 Facts about Olduvai Gorge, the “Cradle of Mankind”

Olduvai Gorge, an unassuming archaeological site in Tanzania, East Africa, has become known as one of the richest paleoanthropological places in the world. Alongside hominin fossils millions of years old, an array of artifacts found there has given researchers incredible insights into the evolution of humankind. Below are eight facts about Olduvai Gorge and our ancient ancestors who made it their home.

Olduvai Gorge demonstrates the longest known continuous record of human evolution.

Olduvai Gorge has steep sides plunging 295 feet down to a ravine that forks into two branches with a total length of around 30 miles. The depth of the crevasse has allowed archaeologists to uncover rich fossil deposits ranging in age from 15,000 to 2.1 million years old, offering unprecedented clues into human evolution. The unique conditions and findings have given rise to the site’s nickname, “the Cradle of Mankind,” although more recent discoveries in Ethiopia and South Africa suggest other locations for the emergence of the very first hominins. In 1979, it was recognized as a UNESCO World Heritage site.

Excavations at Olduvai Gorge were inspired by Charles Darwin.

British archaeologists Louis and Mary Leakey were instrumental in establishing the scientific importance of Olduvai Gorge. Louis Leakey (1903-1972) grew up in Kenya, then a British colony, and was inspired to start excavations in East Africa by Charles Darwin’s The Descent of Man, an 1871 book that proposed that the first human ancestors likely originated in Africa. At that time many archaeologists discounted Africa as the birthplace of humankind and suggested Asia as a more likely candidate, after bones from what we now know as the hominin Homo erectus were discovered in Java, Indonesia. But the Leakeys were convinced Olduvai Gorge, with its deep ravine cutting through layers of time, could yield spectacular results.

Skull fragments revealed a then-unknown species of early hominin.

The Leakeys started working at the site in the 1930s, unearthing a number of stone tools but no bones—for a time, at least.

Mary Leakey (1913-1996) finally discovered a skull fragment in 1959. This intriguing fossil spurred her on, and soon she had unearthed over 400 pieces, allowing her to recreate an almost complete skull. The Leakeys believed it to be a new species of ancient hominin that they named Zinjanthropus boisei (now known as Paranthropus boisei). The skull was heavy-set and ape-like with a large flat face and prominent molars; the press nicknamed the find “Nutcracker Man.” The Leakeys initially believed the fossil to be about 500,000 years old, but further testing showed its true age as roughly 1.79 million years old. (Paleoanthropologists now believe P. boisei lived about 2.3 to 1.2 million years ago.) At the time, P. boisei was the earliest hominin ever found.

Olduvai Gorge yielded ancient stone tools—and the bones of their makers.

Even today, debate continues over which species of early hominin was the first to use stone tools. Current research suggests tool use began about 3 million years ago, but back when the Leakeys were first excavating at Olduvai, the study of human origins was in its infancy. In 1960, the Leakeys’ 19-year-old son, Jonathan, found a skull markedly different from Nutcracker Man: It was much smaller, appeared to have human-like teeth, and probably had a larger brain. The Leakeys announced it as another new species and named it Homo habilis, meaning “handy man,” because they believed this species was the maker of the stone tools discovered years earlier. H. habilis is one of the oldest members of our own genus.

Scientists debate which hominin starting using tools first.

The discovery of Homo habilis upended the human evolution narrative, suggesting that multiple types of hominins were emerging in the same place around the same time. Some archaeologists, while recognizing that Homo habilis did make and use tools, have raised the possibility that the oldest tools at Olduvai may have been made by Nutcracker Man. A 2023 study in the journal Science reported that stone tools dating to 3 million years ago had been found at Nyayanga in Kenya alongside fossils of a Paranthropus species, leading archaeologists to propose that tool-making actually predates the emergence of the Homo genus.

The “Olduwan toolkit” contains the earliest known human technology.

The stone tools found in Olduvai Gorge changed how archaeologists thought of early hominins: it was evidence that human ancestors were able to make useful tools to adapt to their environment. Since the first discovery of such items at Olduvai, similar groupings of early Stone Age tools have been uncovered at other locations, which led researchers to classify these groups as “Olduwan toolkits.” 

These assemblages include at least three types of tools: large round stones used as hammerstones, sharpened stone choppers for processing meat, and knapped stone axes for hunting and cutting. These simple objects provide evidence for the evolutionary shift to tool-making that allowed hominins to butcher larger animals.

The earliest hominins at Olduvai competed with lions, hyenas, and leopards.

Recent research at Olduvai has painted a fuller picture of the environment in which early hominins lived. Animal fossils found alongside stone tools suggest that hominins in Olduvai were living—and often competing for resources—with wild cattle, pigs, hippos, panthers, lions, hyenas, other primates, reptiles, and birds. They had to adapt to a range of habitats, including fern meadows, steppes, waterholes, and woodlands. Researchers also analyzed the stones used to make tools and found that most of them were sourced from about 7.5 miles away, demonstrating that the early hominins were able to plan ahead to collect the best materials with which to make their tools.

Hominins at Olduvai Gorge may have been hunting prey 2 million years ago.

Early hominins are known to have eaten meat, but until recently, the origins of the meat were less clear. The earliest undisputed evidence of hominins hunting dated from 400,000 years ago, and many scientists assumed the relatively diminutive hominins were scavengers, only eating meat when they could steal it from lions or found an animal that died from natural causes.

A 2010 paper in the journal Quarternary Research shed more light on the question. Researchers at the University of Wisconsin analyzed a butchering site at Olduvai Gorge where wildebeest and antelope carcasses had been processed by hominins such as Homo habilis. The researchers looked at the fossilized teeth of the animals to ascertain their ages and conditions, then compared this data to the fossils of animals caught by lions or leopards. They found that early humans tended to kill large, healthy adult antelopes, whereas lions and leopards killed large prey of any age. The findings suggested that early humans were not just scavenging meat, but carefully selecting which animal they would hunt and kill. 

The discovery proposes that hominins began hunting about 1.8 million years earlier than thought, representing an evolutionary step that hastened the development of bigger brains through the consumption of energy-rich meat.

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