(Credit: Daniel Ramos Gonzalez) What color are these shells? The grove snail, Cepaea nemoralis, comes in a range of colors that can be roughly sorted into three groups: yellow, pink and brown. Tracking color has been key to studying the evolution of this snail, however new research published in the journal Heredity highlights differences in the way humans see color that can make categorization a bit trickier (remember The Dress?) “As scientists, to ensure the accuracy of our studies and the subsequent interpretation, it is important that we have a reproducible measure of color,” notes Angus Davison, who led the study. Naked eye observations were compared to results from a spectrometer, a machine that measures the spectrum of light. Humans did a good job calling out the yellow snails, but had less success separating pink from brown, even arguing amongst themselves. What color do you see?