Rio de Janeiro, Brazil - Brazilian sharpnose sharks pulled from waters off the coast of Rio de Janeiro tested positive for cocaine, with high drug concentrations found in the animals' muscles and livers!

Marine biologists from the Oswaldo Cruz Foundation were shocked to discover cocaine in 13 sharpnose sharks.

The study published in the journal Science of The Total Environment marks the first time sharks have tested positive for cocaine.

The predators had concentrations 100 times higher than in other aquatic animals tested to date. What's more, all the female sharks in the study were pregnant. It's unknown what effects cocaine exposure will have on the fetuses.

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Previous research shows that drugs have similar effects on humans and animals, as the BBC reported, though more investigation is needed to determine exactly how narcotics affect behavior.

How the sharks got their noses white is unclear, but researchers think the cocaine ended up in their waters either as run-off produced by illegal labs, or even from the poop of drug users.

It's also possible, but less likely, that drugs dumped at sea by traffickers could be to blame.

Brazilian sharpnose sharks are on the small side, with those in the study averaging just under two feet in length and weighing less than two pounds.

Researchers involved in the study called for more cocaine testing in coastal waters to determine the drugs' origin, and warned that other apex predators eating fish from the coast could be affected. Since sharks are sometimes also consumed by people, there is also a potential public health risk.