Humans have 2 legs.
Bipedalism in Humans
Humans are fundamentally bipedal, meaning we walk upright on two legs. This mode of locomotion distinguishes us from most other mammals, who primarily use quadrupedalism (walking on four limbs). While other animals may occasionally stand or walk on two legs, humans are uniquely adapted for sustained bipedal movement.
Quadrupedalism vs. Bipedalism
| Feature | Quadrupedalism | Bipedalism |
|---|---|---|
| Limbs Used | Four limbs (legs) | Two limbs (legs) |
| Common In | Dogs, cats, horses, etc. | Humans |
| Spinal Orientation | Typically horizontal | Typically vertical |
| Energy Expenditure | Generally less for short distances | More efficient for long distances |
The Uniqueness of Human Bipedalism
Our bipedalism has significant implications for our anatomy, including the structure of our feet, legs, spine, and pelvis. These adaptations allow us to walk, run, and maintain balance on two legs efficiently. While infants may crawl on all fours before learning to walk, this is a developmental phase, and humans are not naturally quadrupedal. Therefore, the correct answer is two legs.
