The whale shark (Rhincodon typus) is the largest known fish species inhabiting the world’s tropical oceans. These filter-feeding giants present a considerable mystery regarding their early life stages and growth. Understanding how they develop continues to challenge marine scientists.
Newborn Whale Shark Dimensions
Whale shark pups are surprisingly small at birth, typically measuring between 16 to 24 inches (40 to 60 centimeters) in length. Their weight is estimated to be only a few pounds (3 to 5 kilograms). This limited data primarily stems from a single, rare observation in 1995 when a pregnant female whale shark was captured off the coast of Taiwan. This individual was found to be carrying approximately 300 pups at various stages of development, confirming that whale sharks are ovoviviparous, meaning the eggs hatch inside the mother and live young are born. Pups are born free-swimming and are immediately independent, receiving no further parental care.
From Pup to Giant
Whale sharks undergo significant growth from their small birth size to their enormous adult dimensions. Adult whale sharks commonly range from 18 to 32 feet (5.5 to 9.8 meters) in length, with the largest reliably measured individual reaching 61.7 feet (18.8 meters). They can weigh between 41,000 to 50,000 pounds (20.6 to 25 tons).
Males generally grow faster than females in their younger years but reach a smaller maximum size, typically around 8 to 9 meters. Females, while growing more slowly, continue to grow larger, often reaching 12 to 14.5 meters. Whale sharks exhibit late sexual maturity, with males maturing around 25 years of age and females around 30 years. They have a long lifespan, estimated to be between 80 and 130 years.
Unraveling the Mystery of Young Whale Sharks
Information about baby whale sharks remains scarce, largely due to the species’ elusive nature and vast oceanic habitat. Only a small number of newborn whale shark pups, estimated between 30 and 40 globally, have ever been found in the wild. Researchers face significant challenges in studying their reproduction and early development due to their extensive movements and deep-diving capabilities, with dives recorded up to 1,900 meters. Recent research suggests that young whale sharks might be found near oxygen minimum zones, which could provide a refuge from predators and a source of food. While specific “nursery grounds” are not yet fully understood, areas like the Galapagos Islands show high concentrations of pregnant females, possibly serving as stopovers before birthing.