Piranhas Bite More Than 100 People in One Weekend

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The article below points out the interesting relationship between piranhas and certain other fish--each serving as both predator and prey for the other. Human fingers and toes get involved as well.
Piranhas attack beach in Brazil: 100 swimmers bitten in 1 weekend | Mail Online:

"A lake used by swimmers in Brazil has been attacked by piranhas that have injured more than 100 people.


Visitors to the inland Barragem do Bezerro dam, close to the town of Jose de Freitas in the Piaui province, were left with bitten heels and toes "