Australian researchers say rising sea levels have wiped out a rodent that lived on a tiny outcrop in the Great Barrier Reef, in what they say is the first documented extinction of a mammal species due to human-caused climate change.

The rodent was known to have lived only on Bramble Cay, a minuscule atoll in the northeast Torres Strait, between the Cape York Peninsula in the Australian state of Queensland and the southern shores of Papua New Guinea. The long-tailed, whiskered creature, called the Bramble Cay melomys, was considered the only mammal endemic to the Great Barrier Reef.

While melomys had been abundant on the island in the 1970s, their populations had dwindled rapidly since over the last few decades, leading them to being listed as endangered. They were last spotted on the island in 2009.

From August to September 2014, scientists conducted a thorough survey effort of the island, using traps, cameras and daytime searches to try to spot and count the species – all to no avail – leading them to conclude that it had likely gone extinct.

The seawater is believed to have destroyed the creature’s small habitat. In March of 2014, the livable surface of the island had shrunk to its smallest point ever and refuge sites used by the critters, such as rock caves and crevices, had started to disappear.

This also led to problems with food. While its diet was poorly researched, melomys were believed to be mostly vegetarian and they had to compete for food with nesting seabirds and turtles.