Fossils of extinct “giant cloud rats” found in the Philippines
Surprise discovery suggests the region was more diversely populated than previously thought.
“These rodents were able to survive climatic changes from the ice age to current humid tropics… what might have caused their final extinction?”
Piecing together fossil remains of jaws and teeth in the Philippines, archaeologists have unearthed evidence of three new giant cloud rat species that lived until just a few thousand years ago.
The new arboreal, herbivorous
species, Batomys cagayanensis,
Carpomys dakal and Crateromys ballik, add to the richness of the region’s native fauna history.
Two of the species, which come from the Phloeomyini tribe, would have been around for about 60,000 years, the team reports in the Journal of Mammalogy, suggesting that the mammals were resilient before they suddenly disappeared.
“These giant rodents were able to survive the profound climatic changes from the ice age to current humid tropics that have impacted the Earth over tens of millennia,” says co-author
Philip Piper from the Australian National University. “The question is, what might have caused their final extinction?”
The remains were discovered in and around Callao Cave on Luzon Island, where excavations seeking insights into early hominins in the Philippines turned up Homo luzonensis fossils in 2010.
The enduring cloud rat species seem to have disappeared around the same time that pottery and Neolithic stone tools appeared and when dogs, domestic pigs and possibly monkeys were introduced, says co-author Armand Mijares from the University of the Philippines.
“While we can’t say for certain based on our current information, this implies that humans likely played some role in their extinction.”
After discovering the fragments, the team added them to existing fossils excavated several decades ago. Altogether, they had only 50 or so fragments to work with.
“Normally, when we’re looking at fossil assemblages, we’re dealing with thousands and thousands of fragments,” says lead author Janine Ochoa, also from the University of the Philippines. “It’s crazy that in these 50 fragments we found three new species that haven’t been recorded before.”