Here are 9 intriguing facts about the Denisovans, a mysterious species in our human ancestry.

Despite the discovery of only a few tiny fossils from the Denisovans—human ancestors who became extinct roughly 30,000 years ago—recent breakthroughs in DNA analysis have provided fascinating insights into their existence. Keep reading for nine key facts about these enigmatic beings.

The discovery of the Denisovans dates back to 2010.

All modern humans today belong to the species Homo sapiens, but our evolution spans across millennia. The earliest human ancestors (known as hominins) appeared around 7 million years ago, and the Homo genus emerged about 2.3 million years ago. Over the past 150 years, scientists have identified at least eight distinct hominins within Homo, ranging from Homo erectus, the first to venture out of Africa, to the small-bodied Homo floresiensis, who stood at just 3 feet, 6 inches tall.

In 2010, Russian researchers Michael Shunkov and Anatoly Derevianko discovered a small finger bone in the Altai Mountains of southern Siberia. The fragment was sent to the Max Planck Institute in Germany, where a team under paleogeneticist Svante Pääbo identified it as belonging to a previously unknown type of archaic human, closely related to both Homo sapiens and Homo neanderthalensis.

Denisovans derive their name from a famous cave.

The first bone fragment was discovered in Denisova Cave, which became the namesake for these mysterious hominins. This remarkable site holds the distinction of being the only known location where multiple hominin groups once coexisted. Evidence found in the cave, including fossils and remnants from various layers of the floor, shows that Denisovans occupied the cave about 200,000 years ago, Neanderthals lived there around 100,000 years ago, and modern humans also inhabited the space. At some point, these extinct hominin groups may have shared the cave together.

Fewer than twelve Denisovan fossils have ever been discovered.

The Denisovans remain particularly enigmatic due to the scarcity of fossils, making it difficult to know what they actually looked like. So far, the only fossils that have been positively identified as Denisovan include three isolated teeth, a skull fragment, a finger bone, half of a broken jawbone, and four other small bone fragments. These remains were recognized as Denisovan through protein or DNA analysis rather than physical traits, leaving many questions about the appearance of these ancient human ancestors unanswered.

Scientists are still searching for additional Denisovan remains. Fossils found in China, Taiwan, and Kyrgyzstan are considered possible candidates, though their poor preservation has prevented any successful DNA extraction or analysis. At this point, it remains uncertain whether these fossils belong to Denisovans or another hominin species.

The Denisovans could be a completely new species—or they might not be.

The Denisovans are the only hominin group recognized as distinct based solely on DNA evidence. Due to the extreme rarity of their fossils—and the fragmentary nature of those found—scientists have yet to determine their physical characteristics. Without a clear anatomical profile, they cannot be definitively classified as a new species or subspecies. For the time being, Denisovans are considered a “population” within the genus Homo.

Neanderthals and Denisovans both trace their lineage to a shared ancestor.

Researchers studying human evolution propose that the ancestor Homo heidelbergensis, which existed between 600,000 and 300,000 years ago, left Africa around 400,000 years ago. Some of these ancestors migrated west into Europe, evolving into Neanderthals, while others moved into central Asia and became the Denisovans.

Hominin groups that stayed in Africa evolved into Homo sapiens. By 60,000 years ago, this group had expanded into Europe and Asia, living alongside Neanderthals and Denisovans for thousands of years.

Denisovans interbred with both Homo sapiens and Neanderthals.

In 2018, a bone fragment found in Siberia was analyzed, revealing it belonged to a teenage girl with a Neanderthal mother and a Denisovan father. This provided the only known evidence of a first-generation hybrid hominin. The girl, known as “Denny,” is believed to have lived 90,000 years ago. DNA analysis shows that Denisovans, Neanderthals, and modern humans were closely related enough to interbreed and produce offspring, with Neanderthals and Denisovans being more closely related to each other than to Homo sapiens.

Modern humans carry traces of Denisovan DNA.

Denisovan fossils have been discovered at only two primary locations: Siberia and Tibet (although a tooth found in Laos may also belong to Denisovans). Despite this, their genetic legacy suggests they once occupied vast regions of Asia. DNA analysis of contemporary humans in Southeast Asia reveals traces of Denisovan DNA, indicating that modern humans in the area likely interbred with Denisovans thousands of years ago and suggesting that Denisovans lived much further south than previously thought.

Genetic evidence from Papua New Guinea suggests that some modern humans may have interbred with Denisovans as recently as 25,000 years ago, hinting that Homo sapiens and Denisovans coexisted in these regions for thousands of years. Today, Indigenous Ayta Magbukon people in the Philippines, modern New Guineans, and Aboriginal Australians may owe 5 to 6 percent of their genetic makeup to Denisovan ancestry.

Denisovan genes may have provided certain advantages to modern humans.

Denisovans inhabited challenging environments, from the frigid steppes of Siberia to the high altitudes of Tibet. Excavations in Laos also indicate that some Denisovan groups lived in the tropical woodlands of Southeast Asia. The diverse environments they occupied suggest that Denisovans were highly adaptable to the climates they encountered. For example, researchers working in Tibet discovered that modern Tibetans may have inherited a Denisovan gene that enabled them to thrive in the low-oxygen conditions found at high elevations.

The reasons behind the extinction of the Denisovans remain uncertain, as does the exact timing.

Some researchers propose that the Denisovans vanished as recently as 20,000 years ago, possibly due to extensive interbreeding with other hominin species, gradually blending them into the broader human population. Another theory is that as Homo sapiens expanded into Denisovan territories, they outcompeted them for resources or brought diseases that contributed to their extinction. As more Denisovan remains are discovered, archaeologists may be able to shed light on the mystery surrounding these early hominins.