Answer: Interesting question! We hadn't heard anything about this before, but we found this claim in a children's book called Stink and the Great Guinea Pig Express by Megan McDonald. It would also make sense, given that the majority of what we eat is green.
In order to have color preferences, you first need to distinguish colors, so let's start with the question: Can guinea pigs see colors? According to one scientific study:
"Guinea pig retinas contain rods with peak sensitivity of about 494 nm and 2 classes of cone having peak sensitivities of about 429 nm and 529 nm. The presence of 2 classes of cones suggests a retinal basis for a color vision capacity. Behavioral tests of color vision were conducted that verified this prediction: Guinea pigs have dichromatic color vision with a spectral neutral point centered at about 480 nm"This is pretty technical stuff, but it basically means that we can see colors, although not as well as the average human. We found one blog commenter who claimed guinea pigs can't see red, although we haven't found any other evidence to support this. According to Guinea Pigs: A Complete Pet Owner's Manual by Katrin Behrend, guinea pigs are "excellent in differentiating colors, particularly yellow, red, blue and green" (p. 46). Another scientific study claims that guinea pigs have "green color sensitivity," so regardless of whether or not we can see red, we should be able to see the color green just fine. (For further debate on what colors guinea pigs can see, take a look at this Guinea Lynx thread.)
Also, scientists have tested guinea pig vision by putting lettuce, a vegetable without much of a smell, in the same colored bowl again and again, so that the piggy learns to associate the food with the color of the bowl alone. The piggy sought out the bowl with the lettuce, even if when the bowls were rearranged. If we couldn't see color and couldn't smell the food, then we'd have no way of running to the right bowl.
So the evidence is pretty clear that we can see most, if not all, colors. But do we have a preference? In our experience, we don't have strong color preferences. We will go into whichever pigloo is convenient at the time, rather than picking one color consistently, for example. However, we did find a high school honors thesis that attempted to test this question. For this thesis, the students had four colored food bowls and water bottles (yellow, red, blue and green), and measured which ones the guinea pigs ate and drank out of the most. They found that piggies ate the most out of the yellow bowl and drank the most out of the blue water bottle. It's a clever experiment, but we'd like to see more evidence before we're ready to believe that yellow and blue are the best colors. The authors admit they had a small sample size, which could be an issue. We're also wondering if there could have been a social aspect to their results; perhaps the dominant piggy picked the blue water bottle and the yellow food bowl, and the other piggies just followed his or her example. (Or maybe the smallest piggy picked those colors, and the dominant piggy kept coming over and purposely stealing from him or her!)
|Yellow food on a blue plate, which are supposedly a guinea pig's favorite colors. (We tend to like red foods, to be honest!)|