Dozens of young penguins have had to undergo rehab after being washed up on the tropical beaches of Rio de Janeiro.

The Magellan penguins that should be in the colder waters of Argentina's Patagonia region need to gain weight before they embark on their long trip back home.

The grey-and-white birds are being taken to the infirmary of a university in Rio, where they are being nursed back to health.

Many of the surviving penguins were badly dehydrated and looked worn out but rescuers are hopeful they will recover fully.

Brazil's environment agency Ibama will be responsible for flying the penguins back to Brazil's south.