Neanderthal Kids Grew Up So Fast—at Least Compared With Their Human Peers—Thanks to Genetic Adaptations to Their Environment

Scientists think Neanderthal children may have had faster growth rates because larger bodies tend to retain heat more effectively than smaller ones

Sarah Kuta

– Daily Correspondent

April 21, 2026 11:14 a.m.

During their first few years of life, Neanderthal children grew faster than Homo sapiens, likely to improve their chances of survival in the harsh environments the species inhabited.

That’s the conclusion scientists reached after analyzing the well-preserved skeleton of a Neanderthal infant who lived between 51,000 and 56,000 years ago in present-day Israel. They report their findings in a new paper published in the journal Current Biology.

In 1992, researchers found the remains of the Neanderthal baby, known as Amud 7, in a cave near the Sea of Galilee. Amud 7, whose sex cannot be determined, is one of just a handful of Neanderthal children whose remains have been discovered around the world.

“The discovery of the Amud 7 skeleton radically changes our understanding of Neanderthal childhood,” lead author Ella Been, an anatomist at Ono Academic College and Tel Aviv University, tells El País’ Miguel Ángel Criado.

For the study, scientists completed a detailed anatomical analysis of Amud 7. Based on the infant’s teeth, they suspect that Amud 7 was roughly 6 months old when he or she died. However, the baby’s skeletal and brain development was more on par with a modern human between the ages of 12 and 14 months.

Researchers saw a similar trend—a relatively young dental age coupled with a seemingly older skeletal and brain age—when they looked at two other Neanderthal infants, a 2-year-old found in Syria and a 3-year-old found in France. “Seeing the same pattern in three different Neanderthal infants shows that this is not accidental,” Been tells NewScientist’s James Woodford.

At this point, scientists don’t know whether Neanderthal babies behaved differently than H. sapiens—for instance, whether they started walking earlier. But the findings suggest that the two species had different anatomical growth rates from birth to roughly age 7, when their development began to overlap.

Why did Neanderthals evolve to develop more quickly in early childhood? This likely has to do with the environmental conditions they encountered, the researchers posit. Living across Europe and Asia, Neanderthals regularly endured long stretches of intense cold. Neanderthal children may have sized up early to help them survive these chilly spells, because larger bodies tend to retain heat more effectively than smaller ones. H. sapiens, meanwhile, evolved in the comparatively warmer climes of Africa, so babies probably didn’t need to grow quite as quickly.

Neanderthals are H. sapiens’ closest known relatives. The two species began to overlap and interact when early humans migrated from Africa to Eurasia. Some individuals interbred, which is why modern humans have some Neanderthal DNA. But around 40,000 years ago, Neanderthals mysteriously disappeared, while H. sapiens continued to thrive.

Neanderthals and H. sapiens shared a common ancestor—possibly Homo heidelbergensis or Homo antecessor—that lived between 765,000 and 550,000 years ago. As a result, the two species shared many of the same genes and probably looked fairly similar. However, they had some notable anatomical differences. As adults, Neanderthals and H. sapiens were roughly the same size, though Neanderthals tended to be shorter and stockier. Neanderthals also had larger noses, wider and lower rib cages, more pronounced brow lines and larger jaws.

When the researchers analyzed Amud 7, they saw that many of these distinct features were already developing. That finding aligns with a 2020 paper, which found that Neanderthals’ rib cages were already different from those of H. sapiens at birth.

Taken together, the research suggests that Neanderthal traits were largely genetically programmed, rather than primarily shaped by their environment or behavior—a question long debated by researchers.

“Not everyone accepts that Neanderthals were born with differences, and some suggest that these differences developed during their lifetime,” Daniel García-Martínez, an anthropologist at the Complutense University of Madrid who co-authored the 2020 study but was not involved with the latest research, tells El País. “The Amud 7 case could be unique to the Near East, but there are others in France and Russia, and they all show similar development.”