Worms attract two new types of hopping mice from obscurity


Two emerging neglected rat species have joined a long list of endemic mammals on Luson, the largest island in the Philippine archipelago and a focal point of biodiversity. Researchers have made their discoveries thanks to worms and luck, and we hope this discovery can help legislators protect threatened ecosystems before it is too late (SN: 6/8/19, p. 5).

New species Rhynchomys labo and R. migan, luxurious athletic skin, pointed snouts and kangaroo-like feet, the researchers reported on June 6 in the journal Mammalogy. Extraordinary rodent mice that once left field workers ignored the standard bait from coconut sticks which were soaked in peanut butter. While inexperienced mice found a trap, scientists have learned that animals prefer a better breakfast: earthworms.

“We tortured our traps with earthworms and the next day we have a dozen of these,” said Eric Ricard, curator of the Utah Natural History Museum at the University of Utah in Salt Lake City.

Rickart has transferred this knowledge to Luson Fields along with Laurence Hainy from the Field Museum in Chicago and many other contributors. In the late 2000s, expeditions to Mount Labo and Mount Mingang revealed two unknown dead mouse populations of more than 1,250 meters and 1,450 meters respectively. After comparing animals with four species of Rhynchomys, the researchers confirmed their findings and pointed to new species according to their mountain habitat.

Scientists hope to find unknown species hiding in high mountains. The diversity of mammals is high on the mountain slopes, also because the associated animal populations are isolated from the peaks. Mice and rodents may have evolved from a single ancestor whose population was spread on arrival in Luson, Ricard said. Then each group adapts to specific conditions that occur over time in different mountains and turn into different species.

“Almost every mountain [in the region] has its own little mouse,” said biologist Arturo Ramirez-Baustasta of the Instituto Nacional Politecancico in Oaxaca, Mexico, who was not involved in the study. “These endemic species represent unique evolutionary and genealogical histories, so the unique source of genetic diversity is lost forever.”

Only about 6% of virgin virgin forests in the Philippines still face decades of depletion of mining and other forests that threaten geothermal mining and development (SN Online: 9/13/18). The disturbed entrance makes the area prone to flooding and landslides, especially during the typhoon season.

Conservation efforts in the Philippines have been successful, according to Ricard, but more safeguards must be made to protect local communities from mice and humans.

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