Some 500 dead penguins have washed up on Brazil's beaches, and stumped scientists are searching for a reason. The birds' bellies were completely empty, indicating they starved to death. The cooler than usual temperatures off the coast could have driven away the fish and squid the penguins feed on, one expert told the BBC. Only 10 dead penguins turn up in a typical year. "What worries us this year, is the absurdly high number of penguins that have appeared dead in a short period of time," said Thiago do Nascimento of the Peruibe Aquarium.