The whale shark holds the title of the largest known fish species inhabiting our planet’s oceans. These gentle giants are characterized by their broad, flattened heads, distinctive patterns of pale grey or white spots and stripes over a dark grey background, and a white belly. Each individual possesses a unique spot pattern, much like a human fingerprint. Whale sharks are slow-moving and are typically found in the open waters of all tropical and warm-temperate oceans globally.
The Whale Connection
The “whale” in the whale shark’s name refers to its colossal size and unique feeding method. Averaging between 18 to 32 feet in length, the whale shark is comparable in size to some whale species. This immense scale makes it the largest non-cetacean animal.
Beyond its size, the whale shark’s feeding strategy closely resembles that of baleen whales, which are also filter feeders. Whale sharks consume vast quantities of plankton, small fish, and fish larvae, despite possessing hundreds of tiny teeth that are not used for chewing. Instead, they employ specialized filter pads within their large mouths to strain food from the water.
Whale sharks utilize two main filter-feeding techniques. They can engage in “ram filtration” by swimming forward with their mouths open, allowing water to flow continuously through their filtering apparatus. Alternatively, they perform “active suction feeding,” where they open and close their mouths to draw in large volumes of water, sometimes even remaining stationary in a semi-vertical position. Their docile nature and non-predatory feeding habits mean they pose no threat to humans.
The Shark Connection
Despite sharing a feeding strategy with whales, the “shark” in its name correctly identifies the whale shark’s biological classification. It is a fish, belonging to the class Chondrichthyes, which encompasses all cartilaginous fishes, including sharks and rays. This class is characterized by a skeleton composed primarily of cartilage rather than bone.
The whale shark exhibits several anatomical features typical of sharks. It possesses five large pairs of gill slits, which open individually to the exterior. After water enters its mouth for feeding, it passes over these gills, where oxygen is extracted before being expelled. The fin structure also aligns with that of other sharks, featuring two dorsal fins, two large pectoral fins, two pelvic fins, and a single anal fin.
Male whale sharks possess external claspers, reproductive organs found in cartilaginous fishes. While its mouth is uniquely positioned at the front of its broad head, unlike most sharks that have a subterminal mouth, this adaptation is directly linked to its specialized filter-feeding. The whale sharkâs skin is covered in dermal denticles, tooth-like scales that give it a rough texture, a common feature among sharks. These characteristics firmly establish the whale shark as a true shark, despite its whale-like size and feeding habits.