What Did Neanderthals Look Like?

Neanderthals, our closest extinct relatives, occupy a unique branch of the evolutionary tree. Recent research shows that all modern humans have a small portion of Neanderthal DNA from prehistoric interbreeding. At the same time, Homo neanderthalensis is a distinct species from Homo sapiens, and there are important physical differences that scientists use to tell them apart.

For one, Neanderthals didn’t have chins. This is actually something Neanderthals have in common with everyone but modern humans, since we are the only known animal species with chins—i.e., a part of the lower jawbone that extends away from the face. Out of all the extinct human ancestors researchers have identified, none of them had this distinctive but seemingly useless feature.

But it’s not just the chins. Neanderthals—who lived in Europe and Asia roughly 400,000 to 40,000 years ago—had other unique, distinguishing features. Here’s what set them apart.

When scientists initially encountered Neanderthal bones, they didn’t know what they were looking at. Researchers unearthed the first known Neanderthal fossils in 1829 and 1848, but it wasn’t until after 1864—when British geologist William King identified another fossil as belonging to a human ancestor he called Homo neanderthalensis—that other scientists went back and identified these earlier fossils as Neanderthal bones.

Overall, Neanderthals were shorter and stockier than Homo sapiens. The Smithsonian National Museum of Natural History estimates the average female Neanderthal height was 5 feet, 1 inch, and the average male height was 5 feet, 5 inches. Their bones were shorter, thicker and more robust than ours, and their pelvises were wider. Researchers have proposed different theories for why Neanderthals evolved with this body type, but we still don’t really know the answer.

Neanderthal skulls also differ from ours in several key ways. Their braincases are oval-shaped, so their skulls appear longer and lower-set than ours. This means that Neanderthals’ foreheads would’ve sloped backward over their skulls. In addition, Neanderthals had more prominent brow ridges and may have had larger and broader noses than modern humans, since the nose holes in Neanderthal skulls appear larger on average than those in Homo sapiens skulls.

But what about fossils that defy easy classification? In July 2025, researchers published a paper in L'Anthropologie reexamining a child’s skull and jaw from roughly 140,000 years ago. The researchers found that the skull has distinct Homo sapiens features, but the lower jaw has Neanderthal features—including the absence of a chin. They suggest that the skull is an example of a child with mixed Neanderthal and Homo sapiens heritage.

Though many animals cannot produce fertile offspring with a member of a different species, some can, including wolves, coyotes and domesticated dogs. Modern scholarship has shown that despite the fact that Neanderthals and Homo sapiens were different species, they were also able to produce fertile offspring. This interbreeding played an important role in human evolution.

When 19th-century scientists first identified Neanderthals, they theorized that the extinct species must have been inferior to prehistoric Homo sapiens. This thinking has shifted as modern research has shown that Neanderthals could do things like light fires and make tools. In addition, recent headlines about the presence of Neanderthal DNA in humans have prompted modern readers to think about their relationship to Neanderthals in a different way.

“Saying that you look like a Neanderthal used to be an insult, and these days people are very proud when they find that they have Neanderthal DNA,” says Ryan McRae, a paleoanthropologist who works with the Smithsonian National Museum of Natural History’s Human Origins Program.

But what exactly does it mean to have Neanderthal DNA? And how did we acquire it?

First, it’s important to understand that Homo sapiens and most human ancestors evolved within Africa. Neanderthals appear to be an exception. Researchers have only found their remains in Europe and Asia, suggesting that they evolved outside Africa and never migrated into the continent. (This also seems to be the case with Denisovans, another human ancestor with whom Neanderthals mated.)

Because of this, researchers believe that interbreeding events between Homo sapiens and Neanderthals took place outside of Africa. Yet at some point, Homo sapiens with Neanderthal DNA migrated back in.

“We evolved in Africa, left Africa but also came back into Africa, and went back and forth many times,” McRae says. “So that Neanderthal DNA within Africa comes from our species going in and out and bringing it with us.”

These interbreeding events happened sometime before Neanderthals went extinct around 40,000 years ago. We don’t know why Neanderthals went extinct, but one reason their DNA may have persisted within Homo sapiens is that it appears to have boosted our immune system. This means that even after Neanderthals died out, Homo sapiens in Africa and other parts of the world were passing on their genetic legacy.

As a result, McRae says “there is some small proportion of Neanderthal DNA in all modern humans.”