Dwarf Cloud Rat Re-discovered After 112 Years

A team of Filipino and American scientists have rediscovered a highly distinctive mammal - a dwarf cloud rat - that was last seen 112 years ago.

According to Samuel Penafiel, the Regional Executive Director for the Philippine Department of Environment and Natural Resources for the Cordillera Administrative Region, the team was conducting the first comprehensive survey of the small mammals of Mt. Pulag National Park, in Benguet Province, completed on 24 April.  Among the results of their surveys was a capture of Carpomys melanurus, the greater dwarf cloud rat, a smaller relative of the giant clouds rats, spectacular animals found only on Luzon Island, but widespread and comparatively well known.  Mt. Pulag is the highest peak on Luzon at 2922 meters above sea level.

Lawrence Heaney, Curator of Mammals at the Field Museum of Natural History in Chicago and Project Leader, said that “this beautiful little animal was seen by biologists only once previously, by a British researcher in 1896 who was given several specimens by local people, so he knew almost nothing about the ecology of the species.  Since then, the species has been a mystery, in part because there is virtually no forest left on Mt. Data, where it was first found”. 

The animal was captured by Danilo Balete, Project Co-Leader and Research Associate of the Philippine National Museum, in a patch of mature mossy forest high on Mt. Pulag, at about 2350 meters above sea level.  “It was in the canopy of a large tree, on a large horizontal branch covered by a thick layer of moss, orchids, and ferns, about 5 meters above ground.  We had suspected from its broad, hand-like hind feet that it lived up in big trees, but this is the first evidence to confirm that,” according to Balete.

Much of the mossy forest on Mt. Pulag National Park where the biologists found the dwarf cloud rat was logged during the 1960s, and few large trees remain.  “The mossy forest has been gradually regenerating, but many local people now have vegetable farms, and some of the mossy forest has disappeared as a result”, said Park Superintendant Emerita Albas.  “Other parts of the park have extensive areas of mossy forest, but where there are roads into the park, the vegetable farms are expanding.  The people deserve to have a place to live and have their farms, but the mossy forest needs to be protected.”

According to Director Penafiel, “the mossy forest is like a giant sponge when it rains, soaking up the water and releasing it gradually.  This produces clean water for irrigation, for household use, for the hydroelectric dams, and also for industry in the lowlands.  The mossy forest gets more rain each year than any other place, up to 5 or 6 meters per year, sometimes more, so it is very important for us all.”

Balete described the dwarf cloud rat as being “a really beautiful animal with dense, soft reddish-brown fur, a black mask around large dark eyes, small rounded ears, a broad and blunt snout, and a long tail covered with dark hair. They weigh about 185 grams.”  The team thinks that the species probably lives only high up in the big canopy trees in mature mossy forest, at elevations from about 2200 to 2700 meters in the high mountains of the Central Cordillera. “Now that we know where to look for them, itwill be possible to learn more.  The cloud rats are one of the most spectacular cases of adaptive radiation by mammals anywhere in the world, with at least 15 species ranging in size from 2.6 kg to 15 grams, all living only in the Philippines. They are a prime example of why biologists refer to the Philippines as ‘the Galapagos times 10”.  The Philippines may have the greatest concentration of unique biological diversity, relative to its size, of any country in the world" said Heaney.

Most of the species that the team documented on Mt Pulag live only in the Central Cordillera, and most live only in mossy forest.  Other unusual species documented by the team are the bushy-tailed cloud rat, a spectacular animal of 1.5 kg with long, flowing black fur that they found to be common in mossy forest (also called cloud forest) at 2600 to 2800 meters elevation, and three species of small rodents that feed primarily on earthworms, one of which was formally described as a new species only in 2006.  Mt. Pulag is the only place currently known that has four species of cloud rats known to be present.

The team found that the pest rodents that cause damage around buildings and in the vegetable gardens on Mt Pulag are not native species, but instead are species such as the Norway rat that were accidentally brought to the Philippines centuries ago.  The native species avoid humans, live in the forest, and cause very little if any economic damage.  Some, like the dwarf cloud rat, probably are not able to withstand much disturbance of their natural habitat.

Above left illustration by Velizar Simeonovski: Carpomys melanurus. Above right photo, by LR Heaney: The mature mossy forest in Mt. Pulag National Park where Carpomys melanurus was rediscovered.

For more information on the Philippine Mammal Project, click here.