Scientists analyzing a museum specimen of western long-beaked echidna have found evidence suggesting that the mammal has lived for many more years in Australia than it was previously thought.

Long-beaked echidnas are known as monotremes - mammals that lay eggs rather than giving birth to live young ones. The western long-beaked echidnas (Zaglossus bruijnii) are one of the world's five egg-laying species of mammals that survive in small numbers in the Indonesian portion of the island of New Guinea.

The International Union for Conservation of Nature (IUCN) has listed the species as "critically endangered," with a significant decline in their population.

It was previously thought that the species became extinct in Australia tens of thousands of years ago during the Pleistocene epoch.

But scientist Kristofer Helgen, from Smithsonian Institution, recently found a specimen of a western long-beaked echidna that was collected from the wild in northwestern Australia in 1901.

The specimen, which was stored in the Natural History Museum in London, was collected by naturalist John T. Tunney in the West Kimberley region of Western Australia for the private museum of Lord L. Walter Rothschild in England. The specimen was then transferred to the Natural History Museum in 1939, after Rothschild's death.

There were no reports on the specimen until 2009, when Helgen visited the museum and re-examined the specimen, revealing that the western long-beaked echidna was reproducing in Australia at least until the early 20th century. This suggests that the species might still exist in some parts of the country.

Helgen is further planning to search for the animal. He hopes to depend on his experience with the species in New Guinea and interview people with the best knowledge about the northern Australian bush, to help in his search.

The findings of the study appear in the journal ZooKeys.