Human Characteristics: What Does it Mean to be Human

Our eyes say it!

Compared to other primates, humans have huge ‘whites of the eyes’, or sclera. This means that humans can easily read each other’s gaze. In experiments, great ape infants usually follow a gaze only when the experimenter also turns his head. But human infants follow the gaze when the experimenter moves only his eyes. The whites of our eyes may help a lot in communicating with one another.

Our big hungry brain!

Did you know that your brain makes up about 2% of your body weight…but uses about 20-25% of your body’s total energy, just for its basic activity? That’s one hungry brain! No wonder it’s good to eat nutritious foods that offer a lot of energy. The brain of a newborn baby is even more amazing, as it takes up about 60% of the baby’s energy as the brain grows at an astonishing pace.

Human Characteristics: What Does it Mean to be Human?

Part of what it means to be human is how we became human. Over a long period of time, as early humans adapted to a changing world, they evolved certain characteristics that help define our species today.

This section of our website focuses on several human characteristics that evolved over the past 6 million years. As you explore the scientific evidence for these characteristics, you will discover that these traits did not emerge all at once or in any one species. There were important milestones along the way. For example, early humans began walking upright before they began making tools. A rapid increase in brain size occurred before early humans began using symbols to communicate. And all of these traits emerged before humans began domesticating plants and animals.

Walking Upright The earliest humans climbed trees and walked on the ground. This flexibility helped them get around in diverse habitats and cope with changing climates.	Tools & Food Early humans butchered large animals at least 2.6 million years ago. By at least 500,000 years ago, early humans made wooden spears and used them to kill large animals.
Bodies As early humans spread to different environments, they evolved body shapes that helped them survive in hot and cold climates. Changing diets also led to changes in body shape.	Brains As early humans faced new environmental challenges and evolved bigger bodies, they evolved larger and more complex brains.
Social Life Sharing food, caring for infants, and building social networks helped our ancestors meet the daily challenges of their environments.	Language & Symbols From pigments to printing presses, symbols changed the way humans lived and provided new ways to cope with an unpredictable world.
Humans Change the World Within just the past 12,000 years, our species, Homo sapiens, made the transition to producing food and changing our surroundings. We have been so successful that we have inadvertently created a turning point in the history of life on Earth.

Human Characteristics: What Does it Mean to be Human

Human Characteristics: What Does it Mean to be Human?

Part of what it means to be human is how we became human. Over a long period of time, as early humans adapted to a changing world, they evolved certain characteristics that help define our species today.

Footer links