An 80 year-old mystery has now been solved.

But thanks to two researchers - Robert Paddle and Kathryn Medlock - we now know that is not true, and that the thylacine that died on September 7, 1936, was not the animal in the famous photographs and video.

After stumbling across a dusty unpublished taxidermist's report, Ms Medlock, who works as honorary curator of vertebrate zoology at the Tasmanian Museum and Art Gallery, realised that the much-filmed thylacine actually died in May 1936, shortly after being photographed.

Later, the remains of the animal were discovered in a cupboard at the museum.

Dr Paddle, a comparative psychologist from the Australian Catholic University in Melbourne, said that Tasmanian Tiger was an old female that had been sold to the Hobart Zoo by Elias Churchill, a trapper from the Florentine Valley.

"The sale was not recorded or publicised by the zoo because, at the time, ground-based snaring was illegal and Churchill could have been fined," Dr Paddle said.

Once the animal died, its remains were sent to the TMAG, but their provenance was lost.

"No records of that have been found in the zoological collection of the museum," he said.

The museum taxidermist made the skin and bones into an educational display, and later handlers did not know that this was the last of the species.

"For a long time, it was assumed that the specimen was lost," Dr Paddle said.

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Years later, researchers tried to locate the remains of the endling specimen - the last of the species - but without success.

Dr Paddle said many still believed Tasmanian Tigers still roam the Tasmanian wilderness.

"I would love it to be true, I would love to be proven wrong. But, they were being hit by cars and trucks in the 1920s. They aren't being hit by cars and trucks anymore," he said.

"In the 1920s, when the species was hanging on by a thread, you could still read newspaper reports about how the species was destroying the sheep industry ... there was the whole argument that prevented the protection of the species until a handful of days before its extinction."

TMAG director Mary Mulcahy said it was "bittersweet" that the mystery had now been solved.

"Our thylacine gallery is incredibly popular with visitors and we invite everyone to TMAG to see the remains of the last thylacine, finally on show for all to see," she said.