The whale shark is an immense creature of the ocean, known for its size and gentle demeanor. Its unique name often prompts a common question: Is this animal a fish or a shark? This article clarifies the whale shark’s biological identity by exploring the distinctions between fish and sharks.
Decoding Fish and Shark Identity
The whale shark is indeed a fish, and more specifically, it is a shark. Fish are aquatic vertebrates that possess gills for breathing, fins for movement, and usually have scales covering their bodies. They are also cold-blooded, meaning their body temperature fluctuates with their surroundings. This classification encompasses a vast diversity of aquatic life forms.
Sharks are a specialized subgroup within the broader category of fish. They belong to the class Chondrichthyes, which distinguishes them by having skeletons made entirely of cartilage rather than bone. This contrasts with bony fish, or Osteichthyes, which have skeletons made of bone. Because sharks meet the general criteria for fish, a whale shark, being a shark, is also classified as a fish.
Key Features of the Whale Shark
The whale shark’s characteristics affirm its classification as both a fish and a shark. Like all sharks, it possesses a cartilaginous skeleton, which provides flexibility and reduces body weight. Whale sharks also feature five large pairs of gill slits on each side of their broad, flat heads, which are used for respiration.
Its fin structure, including two dorsal fins, pectoral fins, pelvic fins, and a large caudal (tail) fin, is characteristic of sharks. The whale shark is known for its filter-feeding mechanism, where it strains plankton and small fish from the water. This feeding method, while unique among sharks, does not negate its fundamental shark characteristics.
As the largest known extant fish species, the whale shark can reach lengths up to 18.8 meters (61.7 feet). This immense size likely contributed to the “whale” part of its common name, as whales are also large marine animals. However, whales are mammals, breathing air and giving birth to live young, while the whale shark, despite its name, remains a true fish. Its distinctive pattern of light spots and stripes on a dark background also aids in identification.