FACT CHECK: Are Sharks Immune To Cancer And All Other Diseases?

Trevor Schakohl | Fact Check Reporter

An image shared on Facebook more than 2,500 times claims that sharks are immune to cancer and all other known diseases.

Verdict: False

Experts told the Daily Caller that sharks do, in fact, get cancer and other diseases. Scientific research supports their assertions.

Fact Check:

More than 400 species of sharks live in the world’s oceans, according to the Shark Research Institute. They all belong to the chondrichthyan classification, which includes other cartilaginous fish like skates, rays and chimaeras.

“Sharks are the only animals that never get sick,” one Facebook post claims. “They are even immune to every known disease including cancer.”

However, peer-reviewed scientific studies conducted over the years have documented forms of cancer and various other diseases in shark species. For instance, a 2016 study in the Journal of Fish Diseases found that one third of at least 44 cases of lesions in 21 species, including sharks, rays and skates, were malignant. Sharks can get infections – bacterial and viral – and parasites too.

The Daily Caller also reached out to experts, all of whom refuted the Facebook post’s claim. (RELATED: Fact-Checking Trump’s Comment On Wind Farms And Cancer)

“This claim is false and has proven false multiple times,” said Melissa Marquez, the marine biologist who founded the Fins United Initiative, an education and conservation program. “Sharks can get an array of diseases, including cancer.”

“Sharks do get cancer but perhaps at a lower rate than other groups,” University of Guelph integrative biology professor Jim Ballantyne told the Caller in an email.

Scientists have been aware of the fact that sharks are susceptible to cancer for more than 150 years, according to Scientific American.

According to Business Insider, the myth that sharks have immunity to cancer dates back to at least the 1970s, when researchers at John Hopkins University observed that shark cartilage could stop blood vessels from growing into tissues, as occurs in cancerous tumors. Another scientist in Florida exposed sharks to carcinogens and found that they didn’t develop tumors, according to Scientific American.

That research formed the basis of the shark cartilage pill industry, which marketed shark cartilage as a miracle cure for cancer, despite numerous studies proving that it has no effectiveness in treating cancer, according to Scientific American. The shark cartilage pill industry has also negatively impacted shark populations, according to the American Museum of Natural History.

Trevor Schakohl

Fact Check Reporter
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