The rarity of blue

Blue poison arrow frog (Dendrobates azureus) from Guyana [Canon 5D, Canon 100mm macro, 2 speedlights 580EX]

The other day I was listening to Radiolab in my car (if you don’t know this program, give them a listen), and the topic of the episode was our perception of colors. I was struck by the statement that the color blue is exceptionally rare in nature and, as a consequence, philologists claim, this is the last color to enter human vocabulary in the course of the evolution of individual languages. This is simply because we rarely need (or needed, historically speaking) to describe things that are blue. I always knew that blue was relatively rare among terrestrial animals, albeit examples of blue species can be found in nearly every major group, and decided to see if the pattern of rarity of blueness is reflected in my photos.

I used the program Picasa, which allows you to filter images by their color information, to do a search for images with blue as the predominant color. I scanned only about 15,000 of my images, but they represented different geographic regions and groups of animals, and thus were representative of my entire image collection. Naturally, I got a lot of hits with blue sky or water, but also a few photos showing blue animals. The most surprising thing was that nearly all blue animals were from the New World: morpho butterflies, Coprophaneus dung beetles, blue crabs (Callinectes), and poison arrow frogs, to name a few. The only non-American species that came up in the search was a Japanese mud crab Ilyoplax pusillus.

Now, there are many animals in Europe, Africa, and Asia with blue colors (lycaenid butterflies, blue-winged Oedipoda grasshoppers, Blue Tits and other birds etc.), but I cannot think of anything that rivals North American bluebirds or morphos. This makes me wonder if the evolution of color classification schemes in human languages that was mentioned in the Radiolab program might have been different among Amerindian tribes that are routinely exposed to blue animals. The only examples of languages that lacked a specific word for blue came from Africa, and the historical examples of languages that coined this word late in their evolution came from Europe. I need to read up on this.

Male blue mud crab (Ilyoplax pusillus) from Kyushu, Japan performing a courtship display (make sure to click on the image to see the entire display) [Canon 1Ds MkII, Canon 180mm macro, 2 speedlights 580EX]

11 thoughts on “The rarity of blue

  1. Pingback: The Weekly Flypaper » Biodiversity in Focus Blog

  2. “I was struck by the statement that the color blue is exceptionally rare in nature…”

    In nature or just on animals? There are lots of blue berries and blue flowers. and when it comes to animals, blue on butterflies and dragonflies/damselflies is common enough.

  3. Dear Dr. Piotr,
    I love your blog, about this post I have some interesting fact, now I live at Ecuador, and here in the Amazonia, Dr. Richard Evans Schultes described a tribe whom were not able to distinguish blue from green. Here you have a link to the page where you could find this information in the Wade Davis’s book “One River” http://books.google.com.ec/books?id=BZhaEjSxQ8kC&q=color&source=gbs_word_cloud_r&cad=5#v=snippet&q=color&f=false
    Best Regards,
    Isaac Mallol.

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