At Thailand’s Richelieu Rock, a whale shark makes a rare appearance. This is no whale but rather the world’s largest fish. Whale sharks can grow up to 12m long, although unconfirmed reports circulate of giants of up to 18m long. This female is about the average size of 8m. There is little to match the awe inspired by an encounter with a whale shark, and for many divers this is the pinnacle of their underwater experience. Their 3000 tiny teeth are rarely used. When feeding they hold their mouths open and feed on plankton, fish eggs and small marine creatures. Ridges down the whale shark’s back are reminiscent of those on leopard sharks’ backs and like the leopard shark, the whale shark is harmless to humans. She has lost the top part of her tail, perhaps due to an attack by a predatory shark when she was a youngster, or possibly a collision with a boat’s propeller. The shark’s fins act like the ailerons on an aircraft’s rudder and wings, helping steer it gracefully through the water. The abstract pattern of spots and stripes gives the whale shark some camouflage from above. Despite being 4 inches thick, the whale shark’s skin can become infected if it’s mucous covering is broken so although it might be tempting to touch or even try and hitch a ride on a whale shark, this practice is highly discouraged. For a long time whale sharks were thought to be oviparous, in other words, hatching from eggs laid by the mother. However since 1995, females have been discovered containing hundreds of hatched pups, proving that the young complete their development inside the mother’s body before birth. Whale sharks do not reach sexual maturity until they are 25 years old, and pregnancies are few and far between, so they are vulnerable to fishing pressures. Shark fin soup is seen as a delicacy and status symbol in many Asian markets. A single whale shark fin can fetch tens of thousands of dollars in some Chinese restaurants. Until this culture changes or legislation intervenes, whale shark numbers are likely to continue falling.