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Mouse Thought Extinct for Over a Century Makes a Reappearance

Comparing DNA samples from eight extinct Australian rodents, researchers in Australia have discovered that a mouse thought extinct for over 150 years still exists.

(CN) --- Scientists in Australia have discovered that a mouse thought extinct for over 150 years still exists.

Comparing DNA samples from eight extinct Australian rodents, as well as 42 of their living relatives, researchers determined that the extinct Gould's mouse was indistinguishable from the Shark Bay mouse still found on several small islands off the coast of Western Australia, according to a study published in the journal PNAS.

The discovery is part of a larger examination into the decline of native species since the arrival of Europeans in Australia.

Lead author Emily Roycroft with the Australian National University declared the find “good news” in the face of the disproportionally high rate of native rodent extinction since European colonization in 1788.

“It is exciting that Gould's mouse is still around, but its disappearance from the mainland highlights how quickly this species went from being distributed across most of Australia, to only surviving on offshore islands in Western Australia. It's a huge population collapse.”

Slightly smaller than a black rat, the social Gould’s mouse lives in small family groups that burrow in dry grass. Gould's mouse was common before European settlement, but disappeared rapidly after the 1840s. It was named after John Gould, an English ornithologist considered the father of bird study in Australia.

In addition to Gould's mouse, the study examined seven other extinct native species. All had relatively high genetic diversity immediately before extinction, suggesting widespread populations prior to the arrival of Europeans.

“This shows genetic diversity does not provide guaranteed insurance against extinction,” Roycroft added.

Evidence suggests these extinctions happened quickly.

"They were likely common, with large populations prior to the arrival of Europeans,” Roycroft explained.

But the introduction of feral cats, foxes, and other invasive species, as well as agricultural land clearing and new diseases, have decimated native species on the continent.

“We still have a lot of biodiversity to lose here in Australia and we're not doing enough to protect it.”

The news comes at a precarious time for Australia, which is experiencing a mouse infestation after years of drought, devastating wildfires and a period of heavy rain that boosted plant growth, creating ideal conditions for the hungry rodents to reproduce exponentially. Currently, farms are overrun with swarms of mice taking up residence in the walls of barns and homes.

The plague has hit farmers particularly hard, though, as they grapple with the costs of pest control and the destruction of their crops.

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