On the Philippine island of Luzon, paleontologists have found the remains of two previously unknown species of giant thin-tailed rats. Scientists believe that they were completely destroyed by the first inhabitants of the archipelago from 2 to 4 thousand years ago. The results of the study were published in the Journal of Mammalogy.
“Both of these species disappeared about two millennia ago and, apparently, not by chance. Around the same time shards of pottery, Neolithic tools and bones of domesticated pigs and dogs appear in the cultural layer. it seems that the first inhabitants of the island were involved in the extinction of these rodents, said one of the authors of the work, professor at the University of the Philippines Armand Mijares.
The so-called thin-tailed or cloud rats (Phloeomys) are the largest representatives of the mouse family in Eurasia. Representatives of modern species of these rodents reach 2–2, 5 kg and 75 cm in length. They live only on the island of Luzon.
Cloud rats are one of the main pests of rice fields, which is why farmers are actively fighting them. In some provinces of the island, people have completely destroyed the population of thin-tailed rats. In addition, mountain dwellers hunt these rodents for meat.
Mijares and his colleagues suggest that several species of cloud rats have already disappeared from the island due to similar hunting in the past. They explored the Callao cave complex, where the bones of a new species of ancient people (Homo luzonensis) were recently found. Initially, they hoped to find new traces of the existence of this species, but instead they found many teeth and fragments of bones from three previously unknown species of cloud rats.
It turned out that these bones had been found before: scientists found them in the storerooms of Philippine museums. Mijares and his colleagues reconstructed the exterior of these rodents and found out when they disappeared.
One of these species of thin-tailed rats, which was named Batomys cagayanensis, disappeared about 60 thousand years ago, back in the glacial era. The other two, Carpomys dakal and Crateromys ballik, became extinct quite recently, from 2 to 4 thousand years ago.
Scientists believe the first Luzonians, who colonized the Philippines around the same time, were involved in their extinction, as well as their pets, which could hunt cloud rats or compete for habitat.
This hypothesis is supported, in particular, by the fact that Carpomys dakal and Crateromys ballik lived in the lowlands, while their modern relatives live mainly in the mountains, less accessible to humans, dogs and pigs.
Other excavations show that after the arrival of humans on the island, the species diversity of many other animals that lived on the plains decreased dramatically. Scientists hope that by further studying the fate of these rodents, the extinction of modern cloud rat species can be prevented.