Digging through the ancient remnants of more than 10,000 rodents might seem like a certain level of Dante’s Inferno to some, but for paleoanthropologist Elizabeth Veatch, it’s a dream come true. That’s because her analysis of rat bones is helping researchers to better understand the lives of ancient “Hobbit” people who once inhabited the oceanic Indonesian island of Flores.
Only first described in 2003 from remains found in a limestone cave, genetic analysis of Homo floresiensis soon revealed that the 107-centimeter-tall (3.6-foot-tall) people were, in fact, their own species of human. At the time of their inhabitation, H. floresiensis ironically lived alongside giants like Komodo dragons, 183-centimeter-tall (6-foot-tall) storks, vultures with a 183-centimeter wingspan, and small elephant-like herbivores called Stegodons who roamed the tropical grasslands. For the last two decades, the science world has long been on the hunt for what wiped out these small humans – answers Veatch hopes will be found in her research.
Tucked away in Liang Bua cave were stone tools, human remains, and some 275,000 animal bones that were mostly from rats. Researchers analyzed 10,000 rat bones and found that they encompassed five species each with their own distinct size, ranging from the tiny mouse-sized Rattus hainaldi to Papagomys armandvillei, also known as the giant Flores rat (which looks more like a cat than a rodent). The various abundances of these different rat species indicate how the ecology of the island changed over time because morphologies of different rat species tend to adapt to their preferred environment. For example, the giant rat would have preferred open grasslands, while P. armandvillei would have liked closed forested areas.
“Our paper is the first that we know of to use the leg bones of rats in this way to interpret ecological change through time, and it provides new evidence for the local environment during the time of Homo Floresiensis,” said study author Elizabeth Veatch in a university press release.
Around 100,000 years ago when H. floresiensis first made an appearance on the island, their cave was littered with giant rat bones dating back to around the same time. Hobbit people vanished from the island around 60,000 years ago, right around the time when P. armandvillei bones began populating the cave.
“The evidence suggests that Homo floresiensis may have preferred more open habitats where they may have been a part of this scavenging guild of Stegodons, storks and vultures,” Veatch said. “We think that when the habitat changed, becoming more forested, Homo floresiensis probably left the Liang Bua area, tracking these animals to more open habitats elsewhere on the island.”