It's All About Contrast - Not Color

One of the volunteers sent in the link to a great press release on "Are Sharks Color Blind?"

The question has been around for a long time - ever since researchers noted that many shark eyes have both rods (night vision) and cones (typically used to tell colors apart during the day). This recent study showed that although they have cones, it is only one type - not surprisingly the one tuned to green light (typical of seawater).

So what do they see? Well remember that vision in the ocean is pretty compromised. Excellent visibility for us underwater is only about 100 feet (much less than a city block). Heck, we can see mountains and such miles away on land, but underwater, it is a different story.

So how about ditching all that extra color information, and just go for contrast. This is what sharks may be doing. Think of the ocean as a perpetual blue-green twilight.

Check out the article for more interesting information on this subject.

See: Are Sharks Color Blind?

Aloha,

Mark