Penguins are washing ashore, in the hundreds, along the coast of Brazil and experts have been unable to explain why.
Marine biologists and veterinarians told the G1 online news site that the Center of Coastal and Marine Studies is investigating what caused the deaths of the 512 penguins found on beaches of the southern state of Rio Grande do Sul. The cause of death should be known in about 30 days.
Calls to the center on Saturday went unanswered.
Biologists at the center told G1 the penguins were migrating north from Argentina in search of food in warmer waters. They say the birds appeared well-fed, unhurt and without oil stains.
Last year, nearly two dozen penguins were sent to California to be resettled in a cooler climate.
Penguins washed up along the Brazilian coast, swept northward by strong currents from the Straight of Magellan. In 2008, 700 penguins landed in Brazil, some so exhausted they could barely lift their heads.
In 2007, lines of Magellanic penguins headed for the sea on Saunders Island, Falkland Islands.