Illustration demonstrating how the 3 brand-new types of fossil cloud rats may have looked. Credit: © Velizar Simeonovski, Field Museum
Fluffy rodents two times the size of a gray squirrel endured for 10s of countless years, and after that suddenly vanished a couple of thousand years back — maybe driven to termination by people.
Rats, by and big, aren’t extremely popular animals. But while you don’t desire an invasion of typical black rats residing in your home, their remote cousins in the Philippines are downright cuddly. These “giant cloud rats” reside in the treetops of misty mountain forests, and they fill an environmental function inhabited by squirrels in the United States. And, it ends up, we have brand-new proof that they’ve been residing in the Philippines for a long period of time — researchers have actually found the fossils of 3 brand-new types of huge cloud rats that lived along with ancient people.
“Our previous studies have demonstrated that the Philippines has the greatest concentration of unique species of mammals of any country, most of which are small animals, less than half a pound, that live in the tropical forest,” Larry Heaney, the Neguanee Curator of Mammals at Chicago’s Field Museum and an author of a research study in the Journal of Mammalogy explaining the brand-new types. “These recently extinct fossil species not only show that biodiversity was even greater in the very recent past, but that the two that became extinct just a few thousand years ago were giants among rodents, both weighing more than two pounds. Their abrupt disappearance just a few thousand years ago leaves us to wonder if they were big enough that it might have been worthwhile to hunt and eat them.”
Photograph of a few of the cloud rat fossils. Credit: Lauren Nassef, Field Museum
“We have had evidence of extinct large mammals on the Philippine island of Luzon for a long time, but there has been virtually no information about fossils of smaller-sized mammals. The reason is probably that research had focused on open-air sites where the large fossil mammal faunas were known to have been preserved, rather than the careful sieving of cave deposits that preserve a broader size-range of vertebrates including the teeth and bones of rodents,” states Janine Ochoa, an Assistant Professor of Archaeology at the University of the Philippines – Diliman and the research study’s lead author.
At the beginning of the research study, Ochoa was taking a look at the fossil assemblages from collapse the Callao limestone development, where a number of years back, researchers found the remains of an ancient types of people, Homo luzonensis. “We were looking at the fossil assemblages associated with that hominin, and we found teeth and fragments of bone that ended up belonging to these new species of cloud rats,” states Ochoa.
Callou Cave website where the fossils were discovered. Credit: Patricia Cabrera
The fossil pieces found by the excavation group in Callao Cave aren’t the only traces of the cloud rats, however — they had the ability to contribute to them some other fossils in the collections of the National Museum of the Philippines. “Some of these fossils were actually excavated decades ago, in the 1970s and 1980s, and they were in the museum, waiting for someone to have time to do a detailed study. When we began to analyze the fossil material, we were expecting fossil records for known living species. To our surprise, we found that we were dealing with not just one but three buot, or giant cloud rat species that were previously unknown,” stated Marian Reyes, a zooarcheologist at the National Museum of the Philippines, among the research study’s authors.
The scientists didn’t have a lots of product to deal with, however — simply fifty approximately pieces. “Normally, when we’re looking at fossil assemblages, we’re dealing with thousands and thousands of fragments before you find something rare and really nice,” states Ochoa. “It’s crazy that in these fifty fragments, we found three new species that haven’t been recorded before.”
The pieces that the scientists discovered were primarily teeth, which are covered in a tough enamel compound that makes them hardier than bone. From simply a couple of lots teeth and littles bone, however, the scientists had the ability to create a photo of what these animals resembled in life, thanks to, in Heaney’s words, “days and days and days staring through a microscope”
By comparing the fossils to the 18 living types of huge cloud rats, the scientists have a good concept of what these 3 brand-new fossil types would have appeared like.
“The bigger ones would have looked almost like a woodchuck with a squirrel tail,” states Heaney. “Cloud rats eat plants, and they’ve got great big pot bellies that allow them to ferment the plants that they eat, kind of like cows. They have big fluffy or furry tails. They’re really quite cute.”
The recently taped fossil types originated from Callao Cave, where Homo luzonensis was found in 2019, and numerous surrounding smaller sized collapse Penablanca, Cagayan Province. Some specimens of all 3 of the brand-new fossil rodents happened in the very same deep layer in the cavern where Homo luzonensis was discovered, which has actually been dated at about 67,000 years back. One of the brand-new fossil rodents is understood from just 2 specimens from that ancient layer, however the other 2 are represented by specimens from that early date all the method approximately about 2000 years ago or later on, which implies that they were resistant and relentless for a minimum of 60,000 years. “Our records demonstrate that 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. The question is what might have caused their final extinction?” includes Philip Piper, a coauthor based at the Australian National University.
Two of these huge rodents obviously vanished about 2 thousand years back, or right after. “That seems significant, because that is roughly the same time that pottery and Neolithic stone tools first appear in the archeological record, and when dogs, domestic pigs, and probably monkeys were introduced to the Philippines, probably from Borneo. While we can’t say for certain based on our current information, this implies that humans likely played some role in their extinction,” states Armand Mijares, Professor in the Archaeological Studies Program at the University of the Philippines – Diliman, who headed the excavations of Callao Cave.
“Our discoveries suggest that future studies that look specifically for fossils of small mammals may be very productive, and may tell us a great deal about how environmental changes and human activities have impacted the really exceptionally distinctive biodiversity of the Philippines,” according to Ochoa. And such research studies might likewise inform us a lot particularly about the effect of human activities, maybe particularly consisting of over-hunting, on biodiversity, notes Heaney. “This is something we need to understand if we are going to be effective in preventing extinction in the future.”
Reference: “Three new extinct species from the endemic Philippine cloud rat radiation (Rodentia, Muridae, Phloeomyini)” by Janine Ochoa, Armand S B Mijares, Philip J Piper, Marian C Reyes and Lawrence R Heaney, 23 April 2021, Journal of Mammalogy.
DOI: 10.1093/jmammal/gyab023
