The whale shark is the largest fish in the world, a gentle giant of the ocean. Despite its immense size, this creature is known for its docile nature, often interacting peacefully with divers.
Average and Maximum Weight
An adult whale shark typically weighs around 18 to 20 tons (approximately 40,000 to 44,000 pounds) and measures about 9 to 10 meters (30 to 33 feet) in length. The largest recorded individuals can reach much greater sizes, with some reports indicating maximum lengths of up to 18 meters (60 feet) and weights of up to 40 tons (about 90,000 pounds).
Why Whale Sharks Grow So Large
The massive size of whale sharks is largely attributed to their specialized filter-feeding diet. They consume vast quantities of plankton, krill, and small fish, which are abundant in the warm, tropical waters they inhabit globally. This consistent access to nutrient-rich food sources allows for substantial growth over their long lives. Whale sharks also exhibit a slow metabolism and can live for an estimated 70 to 100 years, with some estimates reaching up to 130 years. This longevity enables continuous growth over many decades, contributing to their impressive dimensions.
Measuring the Giants of the Ocean
Directly weighing or precisely measuring a whale shark in the ocean is impractical due to their size and migratory behavior. Scientists rely on non-invasive techniques to estimate their dimensions. Photogrammetry is a primary method, using lasers and cameras to project a known scale onto the shark, allowing for accurate length estimations from photographs. Visual estimations are also used, though they are less precise and can vary significantly between observers. The inherent difficulties of studying these large, wide-ranging animals mean that precise measurements remain challenging, leading to variations in reported sizes.
How Whale Sharks Compare
The whale shark is the largest fish on Earth, a cartilaginous fish distinct from marine mammals like whales, despite its name. For perspective, a blue whale, the largest animal on Earth, can reach over 33 meters (100 feet) in length and weigh over 200 tons (400,000 pounds), making it significantly larger and heavier than any whale shark.
Compared to other sharks, the whale shark dwarfs them. The great white shark, a well-known predator, typically measures between 4.5 to 6 meters (15 to 20 feet) and weighs around 600 to 1100 kg (1,300 to 2,400 pounds), a fraction of a whale shark’s size. The basking shark, another filter feeder and the second-largest fish, can reach lengths of up to 12 meters (40 feet), but is still considerably smaller than the largest whale sharks. To provide a relatable comparison, an average school bus weighs between 14,000 and 19,500 pounds, meaning an adult whale shark can weigh as much as several school buses.