Key to Avoiding Skin Cancer: Shark Lotion? Sharks tan, but don't get the disease By Liam Carnahan, Newser Staff Posted Aug 16, 2012 2:51 PM CDT 16 comments Comments Hammerhead sharks have been proven to tan, but the fish don't contract skin cancer. (?strompooper) (Newser) – We're gonna need a bigger bottle of lotion. Researchers think that the key to curbing skin cancer may lie deep under the sea, among the sharks. The giant fish, honored this week by the Discovery Channel, are able to tan, but apparently they are impervious to skin cancer. Scientists aren't sure why, but they hope that by studying the phenomenon, they could eventually develop a "shark lotion" that could give the same protection to humans, reports the Daily Mail. A study at California State University's Shark Lab (yes, really) found that Hammerhead shark pups placed in a shallow pool and exposed to high levels of UV radiation did indeed darken over time. To test the theory, they placed a screen that blocked the UV rays over parts of the sharks' fins, which after being removed resulted in shark tan lines. Meanwhile, attempts to induce skin cancer in sharks have failed. Unfortunately, not all fish are immune to the disease.