Hobbit-like humans may have scavenged Komodo dragons’ leftovers to survive

The reconstructed skull of the extinct Homo floresiensis (Flores Man. nicknamed hobbit) is seen with a Komodo dragon in this composite image.

Prehistoric human relatives, nicknamed “hobbits” due to their short stature, may have been scavengers, rather than skilled hunters capable of taking down big game or building cooking fires, according to new research.

The study adds to growing evidence that Homo floresiensis, which had a brain only slightly bigger than that of a chimpanzee, wasn’t as advanced as scientists previously believed.

Fossils unearthed by archaeologists in the Liang Bua cave on the Indonesian island of Flores in 2003 led to the discovery of the diminutive hominin. The creature had a skull the size of a grapefruit and likely stood about 3.3 feet (one metre) tall.

Excavators uncovered stone artifacts and bones of Stegodon florensis insularis, a bison-size extinct relative of elephants, near the Homo floresiensis fossils. The find suggested the hobbits had hunted with tools to take down the large animals. Burned bones of smaller animals also hinted that the hobbits could wield fire.

Such advanced behavior is considered a key evolutionary trait associated with large-brained hominins such as Neanderthals, Homo sapiens or modern humans, and Homo erectus, an early human that lived between 1.89 million and 110,000 years ago. The potential connection between hunting tools and fire use in Homo floresiensis has even led some researchers to believe that the hobbits were closely related to Homo erectus.

Dr. Elizabeth Grace Veatch, a paleoanthropologist who studies the evolution of the human diet and how early humans interacted with animals, wanted to take a closer look at how Homo floresiensis survived on an isolated island between about 190,000 and 50,000 years ago.

Veatch and her colleagues carried out a multifaceted analysis of Stegodon bones found on Flores, studying what happened to the bones after the Stegodons died.

“I wanted to see if we really could show that H. floresiensis was the hunter that it had been portrayed as for decades,” said Veatch, lead author of the study published Friday in the journal Science Advances and research associate in the Human Origins Program at the Smithsonian Institution’s National Museum of Natural History.

But the study, which included a feeding experiment involving a Komodo dragon, suggests that the hobbits only used their tools to scavenge the raw Stegodon leftovers of the island’s sole carnivorous animal — and Homo floresiensis didn’t use fire to cook the meat.

The finding, combined with previous research, shifts how experts are thinking about Homo floresiensis’ spot on the family tree of human evolution.

Inside a Komodo dragon’s mouth

Thousands of tools have been found alongside Homo floresiensis fossils, suggesting the early hominins were crafting what they needed to process Stegodon meat from the bone out of local rocks called chert, said study coauthor Briana Pobiner, a paleoanthropologist at the Smithsonian Institution.

But the researchers wanted to see whether the markings on the Stegodon bones showed evidence that the hobbits were also hunting the only large-bodied herbivore on the island at the time. Stegodon weighed about 1,260 pounds (570 kilograms) and stood roughly 5 feet (1.5 metres) tall at the shoulder.

The hunt for answers took the researchers to an unexpected place: Georgia’s Zoo Atlanta, where they watched a Komodo dragon named Rinca use its powerful bite to feed on a goat carcass and better understand how the giant lizards leave behind teeth marks on animal bones.

The team used a 3D scanning technique on the goat bones left over from Rinca’s meal to evaluate them alongside the cut marks that humans made using stone tools, as well as Stegodon bones found in the Liang Bua cave.

“After comparing the marks on the Stegodon bones with our sample of Komodo dragon tooth marks and cutmarks, I was surprised by how similar most of the marks were to our Komodo dragon sample,” Veatch wrote in an email.

Komodo dragon tooth marks were also most commonly found on the meatiest parts of Stegodon, while cut marks from the hobbits’ stone tools were found in less choice parts of the animal. The researchers believe that much like how Komodo dragons hunt water buffaloes today, they were using their venomous bite to take down Stegodons — and after the scene was clear, Homo floresiensis swept in to cleave meat from what remained.

The hobbits wouldn’t have been at risk of venom poisoning while scavenging because Komodo dragon venom contains proteins that stomach enzymes would break down, according to the study.

To search for evidence of fire use, the researchers analyzed rodent bones littering the cave, deposited over thousands of years by roosting owls. If hearths had been built in the cave, underlying bones would have shown evidence of charring — but not a single bone out of the 4,500 studied was burned. No Stegodon bones showed char marks either.

The researchers suspect that the few burned bones found in later archaeological layers of the cave’s sediments are evidence of Homo sapiens using the cave from about 46,000 ago, long after Stegodon and Homo floresiensis had disappeared.

A different evolutionary path

Homo floresiensis likely lived off scavenged raw meat, plants and insects, Pobiner said, and they persisted for thousands of years despite the presence of Komodo dragons.

“Given that modern-day Komodo dragons seem to attack humans only occasionally, and almost never attack humans unprovoked, simply living in a group and being wary of Komodo dragons may have been enough for Homo floresiensis to largely avoid becoming their prey,” Pobiner wrote in an email.

But the study highlights that prehistoric human relatives who overlapped in time with Neanderthals and modern humans could have extremely different behavioral adaptations, Pobiner added.

Continued research investigating different aspects of Homo floresiensis since the species’ discovery has changed many initial interpretations about the hominins, said study coauthor Dr. Thomas Sutikna, who was part of the team that found the first fossil and has led research at Liang Bua since 2001.

Veatch is continuing her work to see whether the hobbits consumed other animals to get a better idea of their ecological role within the island ecosystem.

The idea that Homo floresiensis did not hunt or use fire could also signal a different evolutionary path for the hobbits than previously considered. It’s possible that Homo floresiensis was more closely related to a different early Homo species, diverging before Homo erectus appeared.

“A more simplistic behavioral repertoire may indicate an ancestry that separated from the Homo lineage prior to these more advanced behavioral adaptations appearing in later-Homo species,” Veatch said.

The new study reinforces a long-held suspicion that Homo floresiensis is not a dwarfed form of Homo erectus but a descendant of a more primitive Homo habilis-like or Australopithecus-like form that arrived on the island more than1 million years ago, said Dr. Chris Stringer, a research leader specializing in human origins and paleoanthropology at London’s Natural History Museum.

Homo habilis is one of the earliest known species of the Homo genus. The Australopithecus species, like the famed Lucy fossil, walked upright but had a relatively small brain closer in size to that of an ape.

Stringer was not involved in the research.

“It reinforces the minority view that floresiensis does not really belong in the genus Homo and should be redesignated, although choosing a new genus name will not be straightforward without knowing more about its ancestry.”