As many readers pointed out, the images that surfaced in London's Telegraph last month of a massive river snake in Borneo looked a slight slither less than authentic. The truth has surfaced (they were a hoax), and here's how one reader figured it out (no advanced Photoshop skills required).

Curious to get to the bottom of the serpentine mystery, Nathan Chadwick, 29, a librarian at the University of Kansas Medical Center, used a nifty reverse search engine called TinEye. Instead of searching for text, this search engine looks for pixels. To do that, it analyzes an uploaded or linked image and creates a unique fingerprint for it. Once it has that image in its index, it can find duplicate and even cropped, resized and digitally altered versions of it.

The search engine has a limited range now (slightly more than one billion images – a fraction of all of those in the far reaches of the Web), so Chadwick was surprised to find matches for both of the Borneo snake images. One had been a contestant in a 2002 contest to create a cryptozoology image ("a serious hoax" according to the sponsoring Web site, Worth1000.com). An uncropped original, snake-less version of the other image appeared on a few other sites, all of which actually label it as the Congo River.

Chadwick wasn't the only one to locate these revealing sites (commentors on other blogs found them as well, and another SciAm.com reader found one of them on YouTube), but he kindly revealed his sleuthing technique for the rest of us. "My co-workers and I are always obsessed with new ways of finding information," Chadwick tells ScientificAmerican.com. This "is merely one of those great tools that is revolutionizing the way we think about retrieving data."