How can a creature of such enormous size and long-distance migratory behavior cope with a spine twisted in multiple directions? (Whale shark with the spinal deformity not picture; Photo by Jenna Szerlag/Design Pics Editorial/Universal Images Group via Getty Images)
Design Pics Editorial/Universal Images Group via Getty Images
There’s nothing quite like swimming alongside a whale shark. Their sheer size is humbling — they typically measure between 18 and 32 feet (5.5–9.8 m) but can grow even largerm with the biggest ever recorded stretched an astonishing 61.7 feet (18.8 m) — yet their calm presence makes you feel oddly at ease, as if you’ve been granted a moment of quiet in the chaos of the ocean. Every inch of their spotted, streamlined bodies is designed for life on the move, carrying them across entire oceans in search of clouds of plankton and fish eggs. Watching one glide effortlessly through the blue, it’s easy to see how they can be living testaments to the power of evolution.
That’s why when a whale shark shows up with a pronounced spinal deformity, it’s enough to stop seasoned researchers in their tracks.
For the first time, scientists have formally documented a spinal curvature in a whale shark. Whale sharks (Rhincodon typus) are the largest fish in the world, found in warm, tropical, and subtropical waters across the globe. The gentle giants are highly migratory, often traveling thousands of kilometers to reach seasonal feeding grounds, and their patterned skin is unique to each individual (much like a human fingerprint). Their lifespan is still not precisely known, but estimates suggest they can live over 70 years. As a species classified as endangered, they face threats from boat strikes and habitat changes driven by climate and human activity, making the study and conservation of their biology critical for understanding and protecting these iconic travelers.
The shark in question was spotted twice at Ewing Bank, a reef system in the northern Gulf of Mexico that attracts whale sharks during seasonal feeding events. Researchers first encountered the animal in 2010, then spotted it again in 2013, and were immediately struck by its unusual posture. The deformity was astounding in and of itself, but what made this even more remarkable was well it was seeming to cope with it! Observers noted the animal feeding calmly at the surface, swimming with the same slow, graceful movements characteristic of healthy whale sharks. In their eyes, this doesn’t seem like a struggling animal; on both occasions, the shark was actively foraging, feeding on fish eggs (a seasonal food source that draws large numbers of whale sharks to the Gulf each summer). Yet its spine was dramatically arched, curving in multiple directions in a condition resembling kypholordoscoliosis (a combination of kyphosis, lordosis, and scoliosis, which together create a twisting and exaggerated curvature of the vertebral column). In humans, this condition can cause pain and mobility challenges… so seeing it in a whale shark has, rightly, raised a lot of questions. Could a spinal deformity interfere with the shark’s swimming efficiency or energy use? Might it affect how the animal hunts or competes for food? Could it make the shark more vulnerable to predators, disease, or environmental stressors? And how does a creature of such massive size and long-distance migratory behavior compensate for a skeletal abnormality without apparent loss of function?
Whale sharks (Rhincodon typus) are the largest fish in the world, yet they are gentle giants that pose no threat to humans. They are filter feeders, cruising slowly near the surface with their massive mouths open to capture plankton, fish eggs, and tiny organisms. Despite their size, they rely on energy-efficient swimming, gliding through warm, tropical, and subtropical waters across the globe.
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Spinal deformities are rare but not unheard of in marine life. They have been documented in a variety of species, from reef fish to other shark species, and can stem from a variety of causes. Genetic mutations, injuries sustained early in life, nutritional deficiencies, or exposure to pollutants can all result in abnormal skeletal growth. However, cases in large pelagic species are particularly noteworthy because these animals rely on long-distance migrations, streamlined bodies, and efficient swimming to survive. A deformity that affects movement could, in theory, be life-threatening. So to better understand how the shark lived with such a deformity, scientists attached a satellite tag. Tracking data revealed that despite its unusual spine, the shark’s movements and diving habits mirrored those of other individuals in the region! It used similar depths and occupied similar temperature ranges, suggesting the condition did not meaningfully hinder its navigation or feeding. If anything, that the whale shark was able to migrate and forage effectively with such a pronounced spinal curvature just goes to show this species’ adaptability and resilience.
But although it seems the whale shark is doing alright for itself, it has left one crucial gaping question: “How?” One possibility is that the shark’s slow, energy-efficient swimming style allows it to compensate for the curvature without expending extra energy. Another theory is that its filter-feeding diet — which is plentiful and easy to access at aggregation sites — reduces the need for bursts of speed or strenuous hunting, making the deformity less limiting. It’s also possible that their cartilage-rich skeletons maye provide some structural resilience. Or it could just be a case of evolutionary adaptability where over time it possibly developed compensatory muscle patterns or modified swimming motions that has allowed it to survive. While a single case cannot provide definitive answers, it does raise the question about whether similar deformities are more common than previously realized but go undocumented due to the species’ elusive nature.
Perhaps somewhere in the vast blue expanse of the oceans, other extraordinary individuals are silently defying expectations, waiting for us to notice. We’d be wise to remember that the ocean still holds mysteries that can astonish even the most seasoned scientists.