Ilin Island Cloudrunner
Known from two specimens. The island where it lived has been almost entirely cleared
No confirmed photograph exists
Location
Ilin Island, Mindoro, Philippines
Overview
The Ilin Island cloudrunner is a large, arboreal rat with a long bushy tail — and the entire scientific record of its existence is two museum specimens, both collected in 1953 from the same small island off the coast of Mindoro in the Philippines. Since 1953, Ilin Island has been almost entirely deforested for agriculture. A 2009 survey found no evidence of the cloudrunner and almost no remaining forest. It is now listed as Critically Endangered (Possibly Extinct) — the IUCN's way of saying extinction is likely but not confirmed.
Why haven't we found it?
Ilin Island covers roughly 90 km² and the deforestation has been near-total. Cloudrunners are entirely arboreal — dependent on mature forest canopy for both movement and food. If any individuals survived the clearing, they would be in the small remnant forest patches on the steeper hillsides in the island's interior. Those areas have not been surveyed using modern small-mammal trapping methods specifically targeting this species.
Reasons to keep looking
- 1
A related species, the Panay cloudrunner, was rediscovered on the nearby island of Panay in 2012 after an extended absence from records, suggesting cloudrunners are capable of persisting in small and isolated forest remnants.
- 2
Local communities on Ilin Island retain knowledge of large arboreal rats in the forest — whether those accounts describe the cloudrunner specifically or other species is unclear, but the knowledge suggests something large and tree-dwelling was present within living memory.
- 3
The 2009 survey that found no evidence was primarily conducted during daylight hours. Cloudrunners are nocturnal, and the survey methodology was not optimised for detecting them.
Things worth knowing
- 1
Both 1953 specimens were collected by Dioscoro Rabor, a Filipino mammalogist who documented dozens of Philippine species during the 1950s. He is responsible for the only scientific encounter with this animal ever recorded.
- 2
The cloudrunner has never been photographed alive. There are no behavioural observations, no dietary records, and no information about its reproduction. Everything known about it fits on a single page.
- 3
The Philippines has the highest rate of endemic mammal species of any country in the world relative to land area. It also has one of the highest deforestation rates. The Ilin Island cloudrunner is one of dozens of Philippine endemics in equivalent limbo.
- 4
Mindoro Island — the large island nearest to Ilin — supports the Mindoro dwarf buffalo (tamaraw), one of the world's rarest large mammals. The region's endemic species have been systematically underfunded for conservation relative to better-known animals on other continents.
- 5
The cloudrunner family (Phloeomyinae) includes some of the largest rodents in Asia. Several related species on other Philippine islands are also poorly known, with population estimates that amount to educated guesses.