Duck or Rabbit Illusion?

This photo was taken by Flickr Artist Dropped_Stitch during a visit to the Ripley's Believe It or Not! museum in Branson, Missouri. The duck or rabbit reversible image has been around for over 100 years. This particular version came to my attention via Noticias de ilusionario.

What do you see a duck (looking left) or a rabbit (looking right). If you slide your mouse over the image the photo will rotate giving you a slightly differ perspective.

Flickr Artist: Dropped_Stitch
background blacked out by Walt

Jastrow's Cartoon (1899)
The interesting thing about this illusion is that it is frequently credited to Joseph Jastrow 1899.
Joseph Jastrow, an American psychologist, was the first to note this image in his work (see left). He used the duck-rabbit to make the point that perception is not just a product of the stimulus, but also of mental activity – that we see with the mind as well as the eye - source.

I obviously agree with Mr. Jastrow. You may have noticed that I frequently couch my words in setting up illusions in the hope that you will be more disposed to see the image from a particular perspective.

Original in Fliegende Blatter (1892)

The truth though is that while Jastrow used his image in 1899 it had appeared in print at least twice before both times in 1892.

Jastrow's 1899 cartoon version was based on one originally published in Harper’s Weekly (November 19, 1892, p. 1114). The Harper's cartoon, in turn, was based on one that had appeared earlier that year in Fliegende Blatter, a German humor magazine (October 23, 1892, p. 147) - source.

So what do you see in this image a duck or a rabbit? Which version is most effective for you?