For years, the belief that sharks don’t get cancer has captured the imagination of scientists, health enthusiasts, and even the alternative medicine industry. It’s an idea that seems to elevate sharks to a kind of biological superpower status—one that humans can study and, perhaps, mimic. But how true is this claim? The real story is more complex—and far more interesting.
The myth likely gained traction in the 1990s, when a few studies and anecdotal claims suggested sharks had unusual resistance to cancer. Some researchers noticed that shark cartilage seemed to inhibit the growth of blood vessels in tumors. This led to the rise of supplements made from shark cartilage, marketed with the claim that they could prevent or even cure cancer.
However, the reality is that sharks can get cancer. Marine biologists and pathologists have documented tumors in several shark species, including cancers of the liver and intestines. While it may be less common than in other animals, cancer is not absent from shark biology.
That being said, sharks do possess some fascinating biological traits that deserve attention. Their immune systems are incredibly robust, and their bodies are full of unique compounds that may help repair DNA and control abnormal cell growth. Some scientists believe these traits may contribute to lower cancer rates—but they don’t equate to immunity.
Moreover, sharks have been swimming the oceans for over 400 million years, surviving mass extinctions and evolving to thrive in a variety of environments. Their long evolutionary history has given them highly efficient systems for healing and resisting infections, which likely includes some level of cancer resistance. But resistance is not the same as invincibility.
In truth, the idea that sharks don’t get cancer oversimplifies a much more nuanced reality. What’s exciting isn’t that sharks are immune to cancer—they’re not—but that their biology might help us understand how to fight cancer better in humans.
So while we shouldn’t look to sharks for miracle cures, we should look to them as valuable research subjects in the ongoing fight against disease. After all, nature is often the best lab for inspiration—and sharks still have a lot to teach us.