More than 400 penguins from Antarctica and Patagonia, most of them young, have been found dead on the beaches of Rio de Janeiro over the past two months.
Some penguins arrive on Rio's beaches every year, but not in these numbers. So what's going on?
One source believes the cause to be overfishing, which would cause the creatures to swim farther from shore to find fish to eat.
Other possible causes include pollution and rougher seas as a result of global warming.
[Image: Associated Press]