Ancient stone tools and the remains of a butchered rhino found on Luzon have sparked debate among scientists about the early colonisation of the region.
The prehistoric humans were probably related to homo erectus, as modern humans or homo sapiens did not arrive in Southeast Asia until around 50,000 years ago.
Until recently, it was believed Luzon and other Philippine islands would have been impossible for prehistoric humans to reach, as they would not have seaworthy boats.
All of the remains were dated to 709,000 years ago using electron-spin resonance methods, which can date material more accurately than radiocarbon dating. These methods can be applied to substances like tooth enamel and rocks that have been heated, like quartz found in sediment.
The researchers are hoping to uncover more archaeological clues as they continue to dig.
The French National Museum of Natural History-led study, published in the journal Nature, has also prompted a re-think of diminutive humans sometimes known as “hobbits”.
“Our hypothesis is that the ‘hobbit’ ancestors came from the north, rather than travelling eastward through Java and Bali,” said one of the researchers, Dr Gerrit van den Bergh of the University of Wollongong.
“They may have been caught in a tsunami and carried out to sea. Those kinds of freak, random events are probably responsible for these movements of humans and animals. This region is tectonically active so tsunamis are common and there are big ones every 100 years or so.”
Remains of homo floresiensis, the scientific name for the diminutive humans, were found on the Indonesian island of Flores, around 2,000km south of Luzon.
The researchers unearthed tools, including 49 sharp-edged flakes and two possible hammer stones, while 13 rhino bones showed signs of being hit with hammers and one was smashed entirely, possibly to get access to eat the bone marrow.
Also among the remains in Kalinga province were skeletons of a monitor lizard, a Philippine brown deer, freshwater turtles and stegodons, a now-extinct animal in the same family as elephants and mammoths. It is unknown if these animals were killed for food.
Stegodons. Picture credit: Wikimedia