How Fish Hide
Posted: July 1, 2019
When you think camo, do you picture blobs of greyish green and brown that blend in to the forest? The underwater world has its own camouflage.
“Sea”-through: You can’t see what you can see right through! Jellyfish are mostly made of water and mostly clear.
Light-bounce: Magicians use mirrors to trick the eye. So does the herring. Like many fish, it has scales that act like thousands of tiny mirrors.
Light-bright: Some sea creatures light up. And they don’t even need an extension cord or fresh batteries. Their bodies have chemicals that produce bioluminescence. Small patches of light flicker and flash all over the surface of the midwater squid. That makes it hard for a predator from below to recognize the shape of the squid.
Shady business: We can’t even count the number of fish that are dark on top but have light bellies. From above, they disappear against the dark of the deep water. From below, they don’t create a dark shape against the light coming through the waves above.
Copycat fish: Mimicry is how the leafy sea dragons in our story hide themselves—they copy their surroundings. Against a patch of gently swaying seaweed they are almost invisible.
Dress up: The decorator crab is perfectly named. It likes to dress up, hiding under the ocean debris and tiny creatures it plasters all over itself.
Fake fish!: That fish sure has big eyes! But wait. They’re on its tail. Those are called eyespots. Do they scare predators? Do they confuse predators? Scientists aren’t sure.
Chameleons of the deep: Some sea creatures can change their coloring to match their surroundings. For example, look at that flounder on the sea floor. Oh, sorry. You can’t see it? Then you probably didn’t notice the octopus, cuttlefish, or squid either.
Here is the sea, great and wide, which teems with creatures innumerable. ― Psalm 104:25