Unlike other sharks, which have their mouths on the underside of the head, the whale shark has its mouth at the very front of its head. Its tail has a top fin that is much larger than the lower fin. Like in most sharks, female whale sharks are larger than the males. According to some biologists, this skin feature serves as a camouflage for the whale shark when it preys on shoals of fish. The camouflage-spots on its skin, especially concentrated on its head, resemble a shoal of fish, thus attracting approaching shoals of fish instead of scaring them away.
Whale sharks are filter feeders.
They sieve enormous amounts of plankton, which they eat through their gills as they swim. Also, as they swim with their mouths open, they draw masses of water filled with plankton and small fishes into their mouths and through spongy tissues between their large gill arches. After closing their mouths, whale sharks use gill rakes that filter the food from the water. Anything that does not pass through the gills is eaten. Gill rakers are bristly structures in their mouths that trap the small organisms, which they then swallow.