A new study by researchers from London’s Natural History Museum and KU Leuven in Belgium argues that Neanderthals and modern humans (Homo sapiens) should be classified as separate species.
Published in the Evolutionary Journal of the Linnean Society, the research provides evidence to support this claim and aims to help us better understand our evolutionary history.
Neanderthals and humans share a common ancestor, and for years scientists have debated whether they are distinct species or simply different subspecies.
Some have called Neanderthals Homo sapiens neanderthalensis, while others argue for keeping them as a separate species.
This study strengthens the argument for treating them as separate species by examining genetic, ecological, and anatomical differences, as well as how species evolve over time.
Dr. Andra Meneganzin, the lead author from KU Leuven, explains that speciation—the process by which one species evolves into two distinct species—is gradual and complex.
In the case of Neanderthals and humans, this process took over 400,000 years. During this time, the two groups developed differences in their anatomy, behavior, and ability to survive in different environments.
Professor Chris Stringer from the Natural History Museum, a co-author of the study, says that while Neanderthals and humans interbred, they were already on different evolutionary paths.
“When Neanderthals became extinct around 40,000 years ago, they were at the final stage of becoming a distinct species, with reproductive isolation already developing,” he explains.
The study argues that interbreeding alone does not mean two groups are the same species. For example, many bird and mammal species interbreed, yet they are still classified as separate species because of their distinct evolutionary paths.
Fossil evidence shows that Homo sapiens evolved in Africa, while Neanderthals lived in Eurasia for at least 400,000 years. This geographical separation contributed to significant differences between the two species.
Neanderthals were adapted to colder climates, with larger ribcages and pelvises to house bigger internal organs like lungs and hearts. These adaptations helped them survive harsh environments but required more energy and physical effort.
Humans, on the other hand, had lighter, more gracile skeletons and more efficient physiology. Combined with the development of advanced tools and technology, this gave humans a survival advantage during times of rapid climate change and resource competition.
Understanding whether Neanderthals and humans are separate species is important for tracing human evolution. The researchers argue that categorizing them as distinct species helps make sense of the fossil record and evolutionary patterns. Without such distinctions, it becomes harder to determine when new species emerged and how they adapted to their environments.
This study also highlights the need for a more nuanced approach to studying human origins. “By looking at fossils in their geographical and historical context, we can learn much more about the diversity of ancient humans,” says Dr. Meneganzin.
While debates about our relationship with Neanderthals continue, this research provides a clearer framework for future studies.
By focusing on the complexities of evolution and speciation, scientists hope to uncover more about what makes us uniquely human—and how our ancient relatives fit into the story of life on Earth.
Source: Natural History Museum.
