Researchers have discovered that sharks off the coast of Brazil have tested positive for cocaine, leading to wild theories about how the drug entered their systems.

Thirteen sharpnose sharks were purchased from fishermen near Rio de Janeiro by researchers. Upon dissection, tests on the liver and muscle tissue of these sharks revealed cocaine in all samples.

The concentration of the drug was up to 100 times higher than previously recorded in other marine animals.

These findings, published in the…