The great white shark is a formidable marine predator whose impressive size often sparks questions about how large these animals can truly become. This has led to widespread curiosity about the largest specimens ever encountered and scientifically documented.
The Largest Verified Great White Shark
Among the most extensively documented large great white sharks is a female known as “Deep Blue.” She gained significant attention after being filmed near Guadalupe Island, Mexico, in 2013, and later sighted in Hawaii in 2019 near a sperm whale carcass. Deep Blue is estimated to be around 6.1 meters (20 feet) long and could weigh over 2,268 kilograms (5,000 pounds). Her substantial girth suggested she might have been pregnant.
Other scientifically verified records exist for large great white sharks. A specimen measured at 6.0 meters (19.7 feet) was recorded off Ledge Point, Western Australia, in 1987. Another notable female, measuring 6.1 meters (20 feet), was caught off Prince Edward Island, Canada, in 1988, with its length verified by the Canadian Shark Research Centre. These documented cases help establish the upper range of verified great white shark sizes.
Unverified Accounts and Historical Claims
Many popular narratives surrounding exceptionally large great white sharks often lack robust scientific verification. Historical accounts, such as the widely circulated claims of a 10.9-meter (36-foot) shark caught near Port Fairy, Australia, in the 1870s, have been re-evaluated. Studies examined the jaws of the Port Fairy specimen and concluded that the original length was a mistake, estimating its actual size to be closer to 5 meters (16 feet). Similarly, a 11.3-meter (37-foot) shark reported from New Brunswick, Canada, in the 1930s, was later identified as a misidentified basking shark, a different species entirely.
Such discrepancies often arise from the challenges of accurate measurement in the field, photographic distortion, or the anecdotal nature of observations. Fishermen’s accounts, while sometimes based on genuine encounters, can be prone to exaggeration without precise tools for verification. These unconfirmed reports differ from those supported by scientific assessment. The distinction between popular legend and documented biological fact remains important for understanding the true dimensions of these animals.
How Great White Size is Determined
Accurately determining the size of a great white shark, particularly in its natural habitat, presents considerable challenges. Direct measurement of a living, free-swimming shark is rarely feasible due to their mobility and the inherent risks involved. Researchers often employ methods such as photographic estimation, where a shark’s length is gauged against objects of known size, such as a research vessel or a dive cage. For instance, a 3.3-meter cage can serve as a reference point to approximate a shark’s dimensions.
When sharks are caught or recovered, more direct measurements can be taken, though consistency in technique is important. Scientists typically measure from the tip of the snout to the caudal fin in its natural position. For historical specimens where only jaws or teeth are available, scientists use regression equations derived from sharks of known size to estimate the total body length. These estimations provide valuable data, but variations in angles or the shark’s behavior can introduce some uncertainty into the assessment.
Why Giants are Rare
Great white sharks exhibit indeterminate growth, meaning they continue to grow throughout their lives, with females generally reaching larger sizes than males. Despite this lifelong growth, individuals reaching immense sizes are uncommon due to a combination of biological and ecological factors. Reaching extreme old age, which is necessary for achieving record-breaking dimensions, is rare in the wild. Great white sharks can live for 70 years or more, but few survive long enough to attain their maximum potential size.
Various factors contribute to natural mortality rates, including competition for resources, environmental conditions, and interactions with other marine species. Human activities, such as historical hunting for fins and teeth, and incidental capture in commercial fishing gear, have also impacted their populations. As apex predators, great white sharks are naturally less numerous than species lower on the food chain, meaning fewer individuals will grow into true giants.