Cocaine sharks? What’s really happening in Brazil’s coastal waters

Sharks swimming in circles, acting aggressively, and approaching boats fearlessly — it sounds like fiction. But marine scientists are seriously investigating strange shark behavior along parts of the Brazilian coast.

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Акула

Reports suggest that species like the sharpnose shark (Rhizoprionodon lalandii) are exhibiting hyperactivity and loss of natural caution. One hypothesis? Exposure to diluted narcotics, especially cocaine, dumped into the sea by smugglers.

As outlandish as it sounds, there’s precedent. Studies have shown that aquatic animals react to trace amounts of stimulants and pharmaceuticals found in polluted water.

Some research on shark neurotoxicity from chemical exposure suggests these compounds may be disrupting their behavior and sensory systems.

Unusual behaviors and possible causes

Myth or truth?

• Myth: Sharks are addicted to cocaine
  Truth: There’s no evidence of addiction — only reaction to exposure.
• Myth: Drugs are dumped on purpose
  Truth: Often jettisoned by traffickers evading law enforcement.

FAQ — common concerns

• Is it dangerous to swim there?
  In affected areas, yes. Unpredictable animal behavior increases risk.
• How does cocaine get into the ocean?
  Through discarded packets and untreated sewage.
• Is there a solution?
  Stronger waste management and marine monitoring programs.

Interesting fact: U.S. lab tests showed that even caffeine and antidepressants affect shark behavior — which makes the potential impact of narcotics far more concerning.