If you Google the short phrase ‘cow on car’ you are sure to see this image:
Is it real? I put the question to 80 participants as part of an eye gaze experiment in which I and some colleagues used infra-red light eye tracking to see what people looked at when they saw this and other images. At the same time, we asked if they thought the image was manipulated, and if so, how.
What do you think?
Of our experiment participants, 23 were unsure. Of the remaining 57, 11 said that the photo was unmanipulated and 46 said it was manipulated. That means that the participants were divided in opinion 34 to 46, or almost half and half (42.5% to 57.5% to be exact).
Often logic (both good and bad) was employed; several participants posited that the cow had gotten up there because it was a cold day and the car had probably been recently driven as it is not covered in snow, so the hood would have been warm. One participant of Russian origin said that a cow wouldn’t usually do something like that, but in Russia “we can train them to do it.” Many participants said that the car would have been dented if the cow climbed up there, and one participant with a farming background said “I know how much a cow weighs, and that car couldn’t stand up to it.”
The farmer was right of course; the answer is that the image is manipulated, a composite of a BMW Series 3 in a snowy field or plaza near some housing, combined with an image of a perfectly normally situated Holstein  milking cow (below).
Interestingly, there is a second manipulation in the image that most people missed, but that, conversely, a few people used as their main justification for deciding the image was manipulated. Can you see it?
If you can, then congratulations, you’ve spotted what most people didn’t. The second manipulation is difficult to see via something I like to call the ‘hiding effect.’ The hiding effect results from a major manipulation being so eye-catching that the manipulation with a smaller profile goes unnoticed. In this case, it is the blurred out license plate. Despite its obviousness once you notice it, the cow resting on the hood distracts your attention, and indeed in our experiment the blurred license plate only received about 3% of the total attention paid to the image.
The photo above is the original photo of the cow on the BMW. It was uploaded to a Russian photo sharing website named Kazansoft. (I made enquiries to Kazansoft about the photographer and location and I hope to be able to update this post with that information should I hear back.)
The BMW image must have been taken no earlier than 2003, because this E46 version of the Series 3 was manufactured between 2003 and 2005 according to my sources in the Bimmerfest BMW community (who also commented that this BMW has some modifications, for example it may have all wheel drive and someone has added some turn signal black outs and angel eyes as well.) 
The Holstein image was presumably uploaded to Kazansoft some time prior to November 2013 (possibly on cdn.acidcow.com on 29 January 2013 ), because on 18 November 2013 the Surrey Police in England tweeted this entertaining and now relatively well known composite image of the Holstein cleverly spliced onto the hood of the BMW with a useful weather-related warning:
This image went modestly viral, and eventually became a high profile member of Internet fauxtography.
If the percentages hold true on a larger scale to our experiment results, then of the 13,706 retweeters of the post, about 5,800 of them don’t know that the image is manipulated even though many might be suspicious of it. I find that quite interesting. What do you think?
 Thanks to branguscowgirl, Nesikep, tja477t, regolith, and Son of Butch from the Breeds Board forum of Cattle Today for their knowledgeable advice and confirmation that the cattle breed is Holstein.
Thanks to The Museum of Hoaxes for identifying the source of the original photo.
 Thanks to tim330i, sixpot_simon, and Zeichen311 of the Bimmerfest BMW forum for identifying the BMW and providing other interesting information about it.
 According to the image search site TinEye, the oldest internet ‘crawl’ of this image was on 29 January 2013 on cdn.acidcow.com at http://cdn.acidcow.com/pics/20130130/acid_picdump_67.jpg