Are different races subspecies?

No! Races are not subspecies of the human species. There is only one “race”—the human race. So why can’t we sort humans into subspecies like we can with other animals? The answer is that the human species doesn’t have much genetic variation. We are too alike to split into groups.

What is a subspecies?

These two zebras are subspecies within the same species of plains zebra. On the right is Grant's zebra (image by David J. Stang), and on the left is Burchell's zebra (image by Hans Hillewaert).

A species is a group of living things that can breed with each other. We can divide some (but not all) species into smaller groups called subspecies. These groups can still breed, but they have physical and genetic differences. Differences between groups add up when they live in separate places for a long time. This means that we can sort some animals based on their appearance or their DNA.

What’s the difference between race and subspecies?

A long time ago, the words race and subspecies were used to mean the same thing in biology. This was before we knew how much or how little genes could differ between animals. Now we only use subspecies to refer to living things that aren’t human. We only use race when we talk about humans. We often try to group humans by race based on how they look. While humans may look different on the outside, our DNA looks very similar. Because we are so similar, scientists say that we can't use race to sort humans either. Are humans really so alike?

Comparisons of humans, emperor penguins, and chimpanzees. Which of these pairs of animals do you think has the most variation within their species? Taylor Swift and Kanye West by David Shankbone; Penguins by Liam Quinn; Chimpanzees by Delphine Bruyere.

Take a look at the photos on the left. There are three pairs of two members of the same species. Which pair do you think is more genetically similar? Would you guess Kanye West and Taylor Swift are more alike, or two penguins? What about Kanye and Taylor versus two chimps? It may surprise you to learn that penguins have twice as much genetic variation as humans do. And this subspecies of chimp has more genetic variation than all the humans on earth.

Why are humans so similar?

Humans haven't been around as long as other animals. We haven't had enough time to develop much variation in our DNA. Humans also migrate and reproduce a lot. Different groups of humans are never apart long enough for genetic differences to add up. Human DNA is too similar to split us into subspecies or races. So we can't use biology to sort people into groups like we can with animals.

Can we define race based on physical appearance?

Even though our DNA is similar, humans look very different from each other. But the traits we use to guess someone's race don't always work well. Think about skin color. There aren't just a few colors: there are more shades than you can ever count. The traits we use are also independent of each other. For example, being tall doesn’t mean you’ll also have dark hair. No matter which traits we use, there is no good way to group humans using appearance or DNA.

Instead, everyone groups people into races based on the traits they think are most important. The way we categorize people into races changes over time, too. Think about people you know who are Irish or Italian. Today we might categorize them as white, like many people from Europe. But 100 years ago, they were not considered the same race as Americans with European origins. Humans love to organize things into groups. But when it comes to race, these groups tell us more about our culture than they do about our biology.

Additional images via Wikimedia Commons. Baby face by Avsar Aras.