The 19th-Century Discovery Hailed as a 'Missing Link' Between Apes and Humans

In 1891, fossilized bones recovered on the Indonesian island of Java revealed an intriguing long-sought "missing link" between humans and apes.

The remains, which became known as "Java Man," suggested the appearance of a thick-boned being with a flat skull, low forehead, heavy brow ridges and a femur that indicated it stood and walked upright. They belonged to something human-like, but also not quite human.

The find by paleontologist Eugène Dubois electrified the scientific community. By the late 19th century, it was evident to scientists that humans had evolved from other primates, but no fossils had yet been found to support this idea. The remains of Neanderthals had been discovered, but they were clearly close to modern humans, and the only other primate-like fossils that had been found were gibbon-like creatures.

The Java Man fossils—a skullcap and a thighbone, unearthed near the village of Trinil and the Solo River—were hailed as the first of what Dubois called a "human-like transitional form." He named the newfound species Pithecanthropus erectus (Latin for "upright ape-man"). The remains were reclassified in the 1950s as an even closer human ancestor named Homo erectus ("upright man").

Scientists have since discovered an entire family tree of dozens of "missing links" that evolved from ape-like creatures into modern humans over roughly seven million years, mainly in Africa. And yet Homo erectus—Java Man—remains a crucial species in the story of human evolution.

A tremendous amount of focus has been placed on Africa over the past few decades, with models emphasizing "Out of Africa’ scenarios," where modern humans evolved in Africa and then migrated to other continents starting some 80,000 years ago, says paleoanthropologist Michael Petraglia of Australia's Griffith University. "This model tended to diminish interest in the evolutionary history of Asia. However, recent discoveries in China are indicating that Asia was an active player in the human story," he says.

A February 2026 study by Petraglia and his colleagues reviewed recent discoveries in China that indicate a greater diversity of human ancestors than previously expected over the last two million years. They include Homo erectus, which is now thought to have entered Asia up to 1.8 million years ago and lived there until about 100,000 years ago. The discoveries also indicated the "Out of Africa" wave of modern humans—Homo sapiens—interbred at times with archaic human ancestors beyond Africa.

"The interbreeding of Homo sapiens with other species of hominins in Asia remains a central question," Petraglia says. However, "this interbreeding was likely limited to certain times and places.”

Calculations later suggested that Dubois had the timeline of Java Man quite wrong. He thought the fossils dated to between seven and 10 million years ago, during the Pliocene epoch, when theories suggested that humans and apes had diverged. It's now thought the Java Man fossils are up to half a million years old, while other Homo erectus fossils found nearby are up to 1.66 million years old. This places them early in the period when Homo erectus is thought to have lived in Southeast Asia.

Recent research has further refined the timeline for Homo erectus in Asia, with a new study indicating its oldest fossils in China—the Yunxian skulls—date to about 1.77 million years ago.

"Because of issues with context with the sites in Indonesia, the age of the Homo erectus fossils there have never really been clear," explains paleoanthropologist Christopher Bae of the University of Hawaii at Manoa. "In China, this has been less of an issue. "

The Homo erectus fossils first discovered by Dubois as Java Man more than a century ago are now revealed as relics from an important phase of human evolution. Their fossils and the fossils of archaic humans that were closely related have now also been found throughout Africa, Asia and Europe, and scientists now think Homoe erectus was one of the first human ancestors to control fire (although they probably could not make it).

"Archaeological research is showing far more innovations over the last two million years than previously recognized," Petraglia says. Recent discoveries indicate that large-brained human ancestors like erectus in Asia were more "flexible" in their adaptations than scientists once thought, he says. In this way, the original Java Man discovery by Dubois continues to shape scientific understanding of the mosaic of human evolution.

Meanwhile, the fossils themselves have been returned to their place of origin. In 2025, the Java Man remains were repatriated from the Netherlands to Indonesia—more than 130 years after their discovery. The ancient skeleton is just one of 28,000 fossils unearthed by Dubois in Indonesia between 1895 to 1920 that the Dutch government has pledged to return to their home country.