Humans are scientifically classified as apes, a designation based on shared evolutionary history and biological characteristics. While the term “ape” often refers to non-human primates in everyday language, biological science places humans firmly within the ape family. This classification offers a deeper understanding of our place in the natural world.
What Defines an Ape
Biologically, apes belong to the superfamily Hominoidea. This group is primarily distinguished from monkeys by the absence of an external tail, a characteristic resulting from a mutation in the TBXT gene. Apes also possess a larger, more complex brain relative to body size, broad chests, highly flexible shoulder joints, and reliance on vision over smell. Humans retain opposable thumbs, though the big toe has lost this opposability.
The Hominoidea superfamily divides into lesser apes and great apes. Lesser apes, like gibbons (family Hylobatidae), are smaller and arboreal. Great apes (family Hominidae) include orangutans, gorillas, chimpanzees, bonobos, and humans. This grouping recognizes humans as a distinct lineage within this broader primate family.
Our Shared Evolutionary Journey
The evolutionary journey connecting humans to other apes is one of shared ancestry, not direct descent from any currently living ape species. Evidence from fossils and genetics indicates that humans and other great apes branched off from common ancestors millions of years ago.
The earliest apes emerged around 25 million years ago, with the gibbons diverging from the main ape lineage approximately 18 million years ago. The lineage leading to orangutans separated from the African ape and human line roughly 14 million years ago. Subsequently, the ancestors of gorillas diverged between 8 and 9 million years ago. The most recent common ancestor shared by humans, chimpanzees, and bonobos lived in Africa an estimated 6 to 8 million years ago. Fossil discoveries, such as Sahelanthropus tchadensis and Ardipithecus ramidus, provide insights into these early branching points.
Similarities and Unique Human Traits
Humans share numerous biological, genetic, and behavioral similarities with other great apes, underscoring our common heritage. Genetic studies show human DNA is approximately 98.8% identical to chimpanzees, our closest living relatives. Anatomical resemblances include a similar dental structure, the lack of an external tail, and a flexible shoulder joint.
Beyond genetics and anatomy, humans and great apes exhibit shared behaviors such as complex social structures and the use of tools. While many apes demonstrate tool manipulation, humans have significantly expanded upon this capacity. Distinctive human traits include obligate bipedalism, meaning we habitually walk upright on two legs, which involved changes in our pelvis and spine. Our species also possesses highly developed language capabilities, allowing for complex symbolic communication and abstract thought, which emerged between 50,000 and 100,000 years ago.
Humans also have a significantly larger, more complex brain compared to other apes, enabling advanced cognitive functions like abstract reasoning and complex culture. This, combined with a longer lifespan and later maturation, has fostered extensive social learning and cultural transmission across generations. These traits represent intensified developments along an evolutionary trajectory shared with other primates.
Addressing Common Misunderstandings
A frequent misunderstanding is the idea that humans evolved directly from modern monkeys or apes. Scientific evidence clarifies that humans did not descend from any living ape species, but rather share a common ancestor with them. Evolution is not a linear progression with humans at its pinnacle; instead, it resembles a branching bush where various lineages diverge from shared ancestral forms. Each species, including humans, has followed its own distinct evolutionary path since those divergences.
The distinction between the scientific classification of “ape” and its colloquial usage is important. Biologically, “ape” (superfamily Hominoidea) formally includes humans alongside other tailless primates. Colloquial use often excludes humans, leading to confusion. Acknowledging our classification within the ape family does not diminish human uniqueness or intelligence; human intelligence, complex language, and culture are distinct elaborations of traits found across the broader ape lineage.