Dead Penguins Washing up in Brazil

Time reports more than 400 dead penguins, most of them young, have been washing up on Rio de Janeiro's tropical beaches.

While it's common for some birds to get swept up in fast-moving currents off Antarctica and Patagonia, a Brazilian environmental official says there have been more this year than at any time in recent memory.

Rescuers and those who treat penguins are offering several theories.

One veterinarian says overfishing is forcing the birds to swim farther out for food, where they're more likely to be sucked in by strong ocean currents in the Strait of Magellan. He says his zoo has already received about 100 penguins for treatment, and many of them were drenched in oil.

An environmental official says pollution is lowering the animals' immunity, leaving them vulnerable to funguses and bacteria that attack their lungs.

But a biologist says he doesn't believe pollution levels are high enough to affect the birds so quickly and suspects weather patterns could be at fault.