Zoo managers in Dudley are considering issuing their keepers with gas masks after a group of orang-utans had Brussels sprouts introduced to their diet.

The apes at Dudley Zoo have been feasting on surplus supplies of the festive vegetable donated by local supermarkets.

The Christmas favourite has been a big hit with the Bornean orang-utans who have been munching them by the sack load.

But the unfortunate side effect of the apes' new snack is the unpleasant smell that emanates from their enclosure.

It echoes throughout the building, so you know when they've let one off Emma Davis Keeper

Keeper James Harper said the animals - Latin name Pongo pygmaeus - already had a reputation for flatulence even before sprouts were added to their diet.

"Orang-utans are windy animals," he said.

"But because of all the Brussels sprouts they are eating there is quite a pong around here at the moment."

Another keeper at the zoo, Emma Davis, said it is not just the smell that they have to contend with.

"You can certainly hear it and it echoes throughout the building, so you know when they've let one off."