The Gulper Shark (Centophorus granulosus) is another deep sea shark with amazing adaptations. Like fellow members of the dogfish family, the gulper shark possesses two spines on the dorsal fins on its back . Gulpers have a long snout and a slender body ranging from grey to brown to olive in color. One of the most eye-catching and interesting aspects of this shark, however, are its green eyes.
Before I explain how these vibrant green eyes work in the deep see, it might help to get a little understanding about how human eyes work for comparison. Your eyes have a number of components that work together so that you can see contrasting lights and colors. The pupil contracts and expands due to the light entering into your eye. The cones can register color in bright light and the rods understand black and white images in low light. The key to night vision is the rhodopsin which is the pigmented molecules that rods use to absorbs photons and understand light. It might sound a little complicated, but you can click this video on how eyes work to get a better understanding.
Gulper sharks have a different way of seeing than you and I do. Living in the deep waters of the ocean, the Gulper Shark eyes have been evolving since the Jurassic era. The light passes into the cornea (transparent front part of the eye that covers the iris, pupil, and anterior chamber) and back out through the cornea, ultimately letting this shark see an image twice. This helps them to see in the low light that is found in the deep. Now that’s some pretty cool night vision.
Join us next week as we learn all about another amazing shark found throughout the world.
Edited by KC O’Shea
Photography: Andy Murch courtesy of ARKIVE
White, W.T. (SSG Australia & Oceania Regional Workshop, March 2003) 2003. Centrophorus squamosus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 30 June 2015.