|by Nan Criqui|
Nudibranchs also use colors to hide. A yellow nudibranch munching on a yellow sponge or an orange-tipped nudibranch crawling slowly across orange coral is hard to see. Using color in this way is called camouflage. Some nudibranchs actually take in and store some of the coloring substances from the food they eat. If a certain nudibranch eats a red sponge, it can store some of the sponge's red pigment in its body, and turn red too.
One kind of sea slug can even store chloroplasts from the plants it eats. (Chloroplasts are the green-colored parts of a plant that make food using sunlight, water, carbon dioxide, and nutrients.) After it has stored up lots of chloroplasts, the nudibranch can stop eating and let its "borrowed" chemical factories make its food.