Aquarium of the Pacific - Online Learning Center - Species Print Sheet

Whale Shark
There is a year round population of whale sharks in the Maldives, the site of extensive research on these awesome sharks. | Maldives Whale Shark Research Programme
Whale Shark

Species Overview


While its large size might suggest a dangerous animal, the whale shark is actually a gentle giant and will permit divers to approach it closely without exhibiting aggressive behavior. A strikingly handsome fish, its colors and markings are impressive and express an individuality that makes possible repeated identification of individuals animals.

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Geographic Distribution



The whale shark is considered to be a pelagic, open water fish, but it is frequently seen in shallower inshore waters associated with lagoons, bays, and coral reefs. It prefers warm, tropical water temperatures, in a range of 21 to 25o C (69.8 to 77o F), but is more content when the warm water is interspersed with cooler, nutrient rich, upwellings that provide a good source of food.

Physical Characteristics

The largest of the sharks, it is well proportioned and beautifully streamlined even with its large, broad, flat, head. Its large mouth, which can be up to 1.5 m (4.9 ft) wide, extends side to side the full width of the head. It is nearly at the tip of the snout. Unlike most sharks in which the mouth is on the undersurface of the head and set well back on the snout, the whale shark’s mouth is almost at the very front of its head. Short barbels protrude from its nostrils. It has a mouth full of small, sharp, almost scale-like teeth. Its relatively small eyes, (about the size of a golf ball), are located a short distance behind the angle of the jaw and at about the same level. The spiracles are behind the eyes at a similar distance. Five large, vertical gill slits are present just forward of and above the origin of the pectoral fin. The two dorsal fins are placed well back on the body. The first dorsal fin is much larger than the second. The caudal fin is semi-lunate (semi-crescent shaped) with the upper lobe much larger than the lower. A very distinctive characteristic on each side of the upper body is the presence of three parallel, horizontally oriented ridges that start at about where the gill slits end and run the length of the body.

Coloration and color patterns vary from one shark to another. The underbody is white or cream colored. The sides and back have a darker base color with shades of blue, gray, and brown. Vertical and horizontal lines of cream or white create a checkerboard appearance with round spots in the squares giving the impression of checkers on a board ready for play. The dark shaded fins are irregularly marked with round, light colored dots.


Reports about size and weight vary considerably, probably depending on the mode and circumstances of measurement. A male specimen accidentally netted off of Bombay in 1983 was measured at 12.2 m (40 ft) and reportedly weighed 11 metric tons (24,250 lb). A larger specimen was reported from the Gulf of Siam and estimated at 18 m (59 ft), a questioned figure. Most whale sharks observed are 6 to 12 m (19.7 to 39.4 ft) in length. As is the case with many shark species, females tend to be larger than males.

Diet and Feeding

It is interesting that the largest fish in the world utilizes small food items for its nutrition. Although its mouth is huge, its gullet is small and limits the size of prey that it can swallow. The whale shark is a filter feeder and its modified gill rakers can remove food particles from sea water down to 1 mm (0.039 in) in diameter, but most of its food comes in larger dimensions. Along with the small forms of phytoplankton and zooplankton that are caught in its filtering system it will also eat sea jellies, small crustaceans, squid, and small fishes such as anchovies, sardines, mackerel, and similar species.

The whale shark uses a feeding technique very similar to that of the large baleen whales. While the whales use baleen plates as strainers and whale sharks use gillrackers, both open the mouth wide, engulf a large quantity of water and prey, then close the mouth and force the water through the mucus coated strainers that hold food preparatory to swallowing.

This filter-feeding shark may feed passively by simply opening its mouth while it is swimming. It may also feed actively by jutting out its jaws, gulping water into its mouth, closing the mouth and forcing the water through the filtering system and out the gill slits. These sharks have been observed hanging vertically in schools of baitfish while sucking the baitfish into their mouths.



Not a great deal is known about the reproductive process of whale sharks. Males, identified by the presence of a pair of claspers near the pelvic fin, appear to become sexually mature when they reach a length of 8-9 m (26.2 to 29.5 ft), but the size of females at maturity is not known. If, or where, there are specific breeding grounds is also a mystery. It is generally accepted that the species is ovoviviparous, (aplacental viviparity), a method of reproduction in which eggs developed inside the female’s body hatch internally. The embryos have no placental connection to the mother, and are supported nutritionally first by the yolk sac and then by fluids called uterine milk secreted by villi in the internal uterine wall. When the embryos come to term, they are live born.




There is much to be learned about the behavior of whale sharks. Although thought to be highly migratory, little is known about their migration habits or patterns other than the fact that they do seem to appear in certain places at certain times. Their movement has been attributed by some researchers to timing with plankton blooms and changes in water temperature. They are primarily solitary animals, but on rare occasions are observed in aggregations of 100 or more individuals. The reasons for the aggregations are not well understood.






The whale shark, along with other shark species, has a sixth sense provided by the presence of specialized nerve cells, located primarily in the head region, called the Ampullae of Lorenzini. These cells are sensitive to and can detect electromagnetic fields transmitted by other animals. These cells assist the shark in finding food at close range, even in poor visibility conditions.




Because of their size adult whale sharks have little to fear from natural marine predators although observers have reported seeing scars that might indicate a large shark such as the white or tiger or even a killer whale might have attempted a larger meal than it could handle. Juveniles are subject to predation by larger fishes and sharks. One juvenile was found in the stomach of a blue shark and another in the stomach of a blue marlin. Orcas have also been mentioned as predators of juvenile whale sharks.


Whale sharks are exhibited in several aquariums worldwide. Swimming and diving with whale sharks in locations where there appearance is predictable has resulted in an ecotourism business in several parts of the world such as Western Australia, Bahia de los Angeles, Mexico, Belize, and the Philippines.


Amazing Facts





Additional Images

Whale Shark
A gentle giant being "petted" | Courtesy of

Whale Shark
Site for photo identification database | ECOOCEAN Whale Shark Photo-Identification Library