Optical illusion transfixes internet - is it a bunny or a bird?

The internet has been transfixed by video of an animal, with opinion divided on whether it is a bird or a rabbit.

Scientist Dan Quintana posted video of somebody petting the animal, with a caption suggesting it was a bunny.

"Rabbits love getting stroked on their nose," he said.

People responding to the tweet couldn't believe it was a rabbit though, with many saying they thought it was a bird.

"I see a raven. Anyone else?" one person said.

But there were also many in the rabbit camp.

"First I thought it was a bird with its mouth open, then I thought it was a bunny, then I was like nah Issa bird (sic), but it's a f**king bunny," one person wrote.

Turns out it is actually a bird, a white-necked raven from Missouri named Mischief to be precise. His owners at the World Bird Sanctuary said he was the "talk of Twitter".

"Mischief isn't sure what to think of this debate. He says he is a raven," he said on Instagram.

The video was originally posted on May 18, 2017 by the sanctuary's curator of bird training Page Davis. 

But it didn't go viral until this week when it appeared on viral video site Imgur.  It was picked up and posted by Quintana the next day.

Davis told CNN on Monday 18-year-old Mischief is already plenty famous from other viral videos. He talks, flies, paints and even recycles.

"[He's] a very talented bird," she said.