Humans pride ourselves on our supreme intelligence: our clever inventions, and the ability to use them. But the rest of the animal kingdom is gaining on us. Plenty of animals, from octopuses to orangutans, use tools. And now, scientists say, pigeons presented with mammogram results can spot breast cancer.

This sounds completely outrageous—unless you know something about pigeons. They’ve got terrific vision and can learn to use touchscreens. They also consistently outperformed human subjects on a classic logic problem called the Monty Hall dilemma

University of Iowa psychologist Edward Wasserman has studied pigeon cognition for years. "Research over the past 50 years has shown that pigeons can distinguish identities and emotional expressions on human faces, letters of the alphabet, misshapen pharmaceutical capsules, and even paintings by Monet vs. Picasso," Wasserman said this week in a press release. "Their visual memory is equally impressive, with a proven recall of more than 1800 images."

Wasserman’s work caught the eye of Richard Levenson, a pathologist and vice chair of strategic technologies at UC Davis. Levenson wondered if the pigeons could learn to interpret medical images.

This is hardly an easy or straightforward task. Radiologists train for years to learn how to read the nuanced visual information in slides, X-rays, and MRI results. Could a group of pigeons get the basics in just a few days?

They sure could. In a paper published this week in PLOS ONE, Levenson, Wasserman, and their colleagues reported that the trained pigeons could tell the difference between cancerous and normal tissue. And the pigeons were really, really good at it. 

Image Credit: © 2015 Levenson et al

Researchers first trained the pigeons to spot abnormalities using a process called operant conditioning, in which the birds were rewarded with food only when they chose the right image between two histology slides. After only 15 days, the pigeons could easily identify which slides showed cancerous cells and which didn’t. 

To make sure the birds weren’t just memorizing the images, the researchers began using brand-new images that the pigeons had never seen before. The pigeons continued to ace the test, spotting breast cancer with 85 percent accuracy. And it only got better from there: When the researchers combined the results of four birds, the flock’s accuracy rate reached a mind-boggling 99 percent.

The pigeons also learned to scan mammogram results for evidence of cancer in little lumps of calcium called microcalcifications. Again, the pigeons nailed it. Their success rate was lower this time, only 72 percent—but that still puts them on par with human radiologists.

Does this mean we’ll soon have white-coated pigeons in our hospitals? Not exactly. Wasserman and Levenson hope to use the birds’ talent for reading medical images to develop better imaging and image-reading techniques. Pigeons won’t replace radiologists in the clinic, but they may pick up some of the grunt work. 

“While new technologies are constantly being designed to enhance image acquisition, processing, and display, these potential advances need to be validated using trained observers to monitor quality and reliability," Levenson said in the press release. "This is a difficult, time-consuming, and expensive process that requires the recruitment of clinicians as subjects for these relatively mundane tasks.

"Pigeons' sensitivity to diagnostically salient features in medical images suggest that they can provide reliable feedback on many variables at play in the production, manipulation, and viewing of these diagnostically crucial tools, and can assist researchers and engineers as they continue to innovate."