Polar Bear Questions
Recently, I received this great question from Anna, an avid viewer of the explore.org Northern Lights Cam, which has been in full swing this spring: “What colors can polar bears see? Are they able to see the colors in the northern lights?”
Anna, what an amazing thing to wonder! You can never be 100% certain that others—humans or animals—perceive the world in the exact same way that you yourself do. This is true for many things in life, including color, the perception of which is determined by whether one has dichromatic or trichromatic vision.
Trichromatic vision is a type of color vision that relies on three types of color receptors (cones) in the eye, each sensitive to different parts of the color spectrum. Usually, these cones are particularly sensitive to colors within the spectrum of, respectively, blue, green, and red light. This type of color vision provides for a great range of color discrimination, allowing the brain to compare and contrast the signals from all three types of cones to create a detailed picture of the color being viewed. Trichromatic vision is the most common type of color vision in humans and many other animals.
Dichromatic vision, on the other hand, is a type of color vision that relies on only two types of color receptors. These two types of cones are typically sensitive to blue and green light, or to blue and red light. Individuals with dichromatic vision can still see color, but their ability to distinguish between different colors is reduced compared to those with trichromatic vision. People with dichromatic vision are often referred to as colorblind, although this term is misleading because they can still see colors, just not as many as someone with trichromatic vision.
All that being said, let’s get back to your question!
To my knowledge only two peer-reviewed studies have directly investigated polar bear color vision, each involving a single bear (see below for references). One study was behavioral, while the other was based on a dissected eye from a dead polar bear. Both assessments agreed that polar bears likely have only two types of cones, and therefore have dichromatic vision. One hypothesis is that polar bears are not particularly great at seeing the color green. However, because so few polar bears have been studied, additional data is needed to know exactly what their color vision capabilities are. Until we learn more, the answer is: yes, polar bears experience the beautiful, swirling aurora—but it may be less colorful than the one you and I see!
Dr. Thea Bechshoft is a polar bear scientist based in Aarhus, Denmark, and a consulting scientist for Polar Bears International. She is the author of the popular Polar Bear Questions page on Facebook, republished here with permission.
Levenson, D.H., Ponganis, P.J., Crognale, M.A., Deegan II, J.F., Dizon, A. & Jacobs, G.H. 2006. Visual pigments of marine carnivores: pinnipeds, polar bear, and sea otter. Journal of Comparative Physiology A: 192(8), 833-843
Ronald, K. & Lee, J. 1981. The spectral sensitivity of a polar bear. Comparative Biochemistry and Physiology, Part A: 70(4), 595-598