Humans, a history

Ancient human ancestors were walking upright as early as 7 million years ago, per new peer-reviewed research published last week in Nature, which examined a set of leg and arm fossils from Sahelanthropus tchadensis, humanity’s earliest known non-ape ancestor.

🧍 A deeper dive… The discovery implies that bipedalism – aka walking on two feet – was one of the first traits separating early humans from chimpanzees, since scientists believe the two species’ lineages diverged around this time.

• Other distinguishing human characteristics are thought to have developed more recently, like the ability to make and use tools (Homo habilis | ~2.4 million years ago), a large and complex brain (Homo heidelbergensis | ~650,000 y.a.), and the capacity for modern-day language (Homo sapiens, aka us | ~200,000 y.a.).
• The question of why our ancestors started walking on two legs is much debated among scientists, but most of them agree that bipedalism helped early humans develop bigger brains so they could better control their now freed-up forelimbs.

🧠 In the know: Humans first evolved in Africa, and much of our early development likely occurred on the continent. To date, every single fossil of early humans living between 2 million and 7 million years ago has been discovered there.

+Fun fact: The idea that bipedalism is linked to the brain development of early humans was first proposed by none other than Charles Darwin, though he mistakenly thought our larger brains came before we started walking upright.