In this episode of Shark Academy, Jonathan explains countershading and other shark colorations.
Do they need camouflage? I’m Jonathan Bird and this is Shark Academy!
Most people, when they imagine a shark, think of something like this: a reef shark, with the classic sharky look. Almost all sharks of this type are grayish with a darker top and lighter underside. This is called countershading. What is it for?
Imagine sunlight falling on a shark with no countershading. The top would be illuminated more brightly than the underside. This would make the shark very easy to see, and its shape is obvious. However if you darken the top of the shark so that it matches the brightness of the underside when sunlight falls on it, now it’s much harder to see, and its shape has been disguised. That is countershading, and it’s what sharks do to help blend in while swimming in plain sight.
Other sharks like the Wobbegong live entirely on the bottom and hunt by ambushing their prey. They have evolved complex coloration and camouflage to blend in to the sea floor.
The Whale shark? Well, in addition to counter shading it has spots on top. Biologists think these help the shark use the dappling of sunlight near the ocean surface to disguise their shape.
Why does the world’s biggest fish need camouflage? Well, that’s anyone’s guess!
Don’t go away! If you’re interested in sharks, there are more than 30 Shark Academy episodes to watch! You can also join my underwater adventures on Jonathan Bird’s Blue World!