By Casey Gilman
For both hunters and the hunted, being cryptic is imperative. By mimicking the patterns, shapes and architecture of their surroundings, animals have evolved extraordinarily clever ways of camouflaging themselves against the multi-textural world they live in. But, according to Lydia Mäthger from the Marine Biological Laboratory, USA, animal eyes can still present a problem.
“By definition,” she says, “the pupil has to be a black hole that lets light into the retina. In most animals it has a very regular shape. And anything that has a very regular shape is relatively easy to detect against an irregular background.”
Cuttlefish, rays and skates may have found a way around this. They all have unusually shaped pupils: U-shaped, W-shaped, and some are even more complex. One reason for these shapes might be camouflage, but Mäthger says that this idea had never been tested. Read more…
Photo Caption: A little skate (Leucoraja erinacea) resting on sand. Credit: Lydia Mäthger.