Humans are primates--a diverse group that includes some 200 species. Monkeys, lemurs and apes are our cousins, and we all have evolved from a common ancestor over the last 60 million years. Because primates are related, they are genetically similar. Human DNA is, on average, 96% identical to the DNA of our most distant primate relatives, and nearly 99% identical to our closest relatives, chimpanzees and bonobos.
What do most living primates have in common?
- Large brains (in relation to body size)
- Vision more important than sense of smell
- Hands adapted for grasping
- Long life spans and slow growth
- Few offspring, usually one at a time
- Complex social groups
Seeing in Living Color
Most mammals, including pottos and certain other primates, are colorblind-they can't see the color red. Yet humans and many other primates perceive a full spectrum of color. The color vision that humans take for granted may have evolved in primates because it helped them to pick out ripe red or orange fruit against the green forest background. Color vision may also help some leaf-eating monkey species to pick out the most nutritious green leaves.
Pottos and most other "lower" primates are active at night, so it's not surprising that many of them never evolved the ability to see the color red. Reddish colors are very hard to see at night, even with full color vision. Although the eyes of many "lower" primates are specially adapted for night vision, these animals rely more on smell than sight to find food and communicate with each other.
What Do You See?
A small proportion of humans are colorblind. If you don't see the number "5" in this image, you have red-green colorblindness, the most common form. Because of DNA differences, colorblindness is much more common among men than among women. As many as one in 14 men of European descent has red-green colorblindness.