Currently renowned for the darker side of immigration policies, Manus Island in the South Pacific is normally in the news for all the wrong reasons. But scientists studying the wildlife on the isolated tropical island have found a resident who, despite having lived there for thousands of years, has evaded the attention of zoologists until now. The newly described “detainee” of the island is not a refugee this time, but a species of giant rat.

Researchers have published a new study unveiling Rattus detentus, named after the Latin word for “detained,” as a nod to the current situation in which Australia is sending asylum seekers to detention camps on the Papua New Guinean island for processing, as well as a reference to the long time that the rat has been living there itself. 

It has long been suspected that a large rodent was scurrying around the island, with accounts from the local residents and gnawing marks found on tough nuts from the Canarium indicum tree. But it wasn’t until a partial skeleton was handed to a researcher in 2002 that there was finally hard evidence for the rat's existence. Now, in the Journal of Mammalogy, researchers have officially described the animal for the first time.

“I’ve been looking for this rat for 30 years,” Professor Tim Flannery, one of the authors of the new study, told the Guardian. The rodent is one of the largest rats to be found across the entire Malay archipelago, weighing in at around 0.5 kilograms (1.1 pounds), though this is easily surpassed by the current record holder, the Bosavi woolly rat, which tips the scales at an impressive 1.5 kilograms (3.3 pounds).

The new species, however, is distinguished by its coarse fur and short tail, and is even represented in the fossil record, as its remains have previously been excavated from a site on the island that dates to the Late Holocene. This reveals to the researchers that the rodent has been present on the island for quite some time, giving the species time to evolve into its relatively large size.

Unfortunately, the researchers discovered the rat just in time, as it now seems to be quite a rare occurrence. Despite being known about by the islanders, even local field researchers who know the landscape and vegetation have a difficult time finding the animal. This, claim the researchers, suggests that the giant rat could well be endangered.