Bornean Tree Mouse
Large Pencil-tailed Tree Mouse (Chiropodomys major) - Danum Valley, Malaysia
I would occasionally see these arboreal mice scampering about in the branches or on vines in the jungle at night. Assuming I have IDed this species correctly this mouse is endemic to Borneo, it is currently listed by IUCN as data deficient because it is not clear where the limits of distribution are and there is little info available on its population status. It seems to be common in Danum Valley, where on some nights I would see multiple individuals but at other times I wouldn't come across any for extended periods of time. The genus Chiropodomys, pencil tailed tree mice, contains six species all of which are found in Southeast Asia. Only one of them, Chiropodomys gliroides, is common and widely distributed, and has been extensively studied, based on the range this must be a lesser known species, specifically C. major if I am correct. Based on my limited experience Danum valley atleast seems to have a large population of these mice, this may not represent their overall population health as Danum valley represents one of the healthiest and most undisturbed tracts of lowland dipterocarp forest remaining in Borneo. There may have been more mice than normal as well due to the fact that it was a mast year meaning many more trees were fruiting, it is possible and I would say even likely that the abundance of fruit and seeds inflates the population of certain species and perhaps this is one of them. Members of the Chiropodomys genus are all arboreal and all subsist on an entirely vegetarian diet.