Our smallest ancestors were smaller than you ever thought – new fossils prove it

On Flores, a remote island in Indonesia, scientists have unearthed fossils that show how small some of our ancient relatives were — so small, in fact, that they might have walked right under your coffee table.

These are not “humans” in the sense of the species we know, but hominins, distant relatives in our evolutionary tree.

The recent discovery at Mata Menge, an archaeological site on the island, pushes the boundaries of what we thought was possible for hominid species: it revealed bones and teeth belonging to some of the smallest adult hominins ever found.

The type in question, Homo floresiensis— affectionately known as “the Hobbit” — was first discovered in 2004 in Liang Bua Cave (now known as Hobbit Cave) on the same island. At the time, we thought these hominins were only about 3.5 feet tall.

Now you’re probably thinking, “Why can’t this just be a case of dwarfism in early humans?”

This question also preoccupied the scientists at first. However, after detailed analysis, it became clear that this was not simply a case of pathological dwarfism, which would indicate an anomaly or exception within a population of normally larger individuals.

Instead, Homo floresiensis represents a special species that evolved its small size through a natural process called island dwarfism. When species are isolated on islands with limited resources and smaller predator populations, they tend to become progressively smaller over generations. (Island life can cause animals to evolve in strange ways – read this article about the rattlesnakes on Santa Catalina Island to learn more.)

Newly excavated Homo floresiensis Bones confirm that they were once even smaller

Recent discoveries at Mata Menge included a humerus (upper arm bone) and several teeth dated to about 700,000 years ago—much older than the Liang Bua specimens. And here’s the amazing thing: The humerus is up to 16% shorter and thinner than the already delicate bones of the previously discovered specimens. The groundbreaking findings are detailed in a study published August 6, 2024, in Nature communication.

Here again, the skeptics among us might ask: “What if the humerus simply belonged to a young specimen of this species?”

To clarify this, the researchers examined the microstructure of the bone, focusing on the presence of secondary “osteons” – structures that form as bones remodel and age. The density of these osteons, as well as the relative thickness of the cortical bone, provided clear evidence that the individual was well into adulthood at the time of death.

To make sure no stone was left unturned, they also compared the humerus to a variety of fossil and modern human bones to ensure that its small size was not the result of a developmental abnormality. The analysis showed that the bone’s features matched those normally found in adult individuals, not subadults or juveniles.

This discovery, along with the results of other tiny fossils discovered at this site, strongly suggest that these even tinier specimens of the species were part of a long-standing population specifically adapted to the unique environmental conditions of Flores.

Imagine the life of these tiny hominins: navigating a world of vast flora and fauna, avoiding the island’s unique predators such as large birds of prey or other prehistoric creatures, while developing simple but effective tools to survive. This is an extraordinary story of survival against all odds in an environment that would have tested their resilience to the limit.

These fossils also deepen the mystery surrounding the evolutionary origins of Homo floresiensisSome of Mata Menge’s teeth resemble those of earlier Homo erectus from Java, suggesting a possible ancestry connection. These new bones and teeth from Flores support the theory that Homo floresiensis developed from Homo erectuswhich itself was a species with a significantly larger body structure.