Hearing tests for polar bears

How do you test a polar bear's hearing? It sounds like the start of a joke, but it's exactly what some animal experts in America have been up to.

Scientists in California are trying to find out if the noise of Arctic ice melting is affecting bears' hearing.

The Arctic used to be really quiet, but its ice, which is vital for the bears' survival, is melting and more people and industries are using the area.

Now experts want to find out just how sensitive the bears are to the noises.

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They're worried the increase of noises created by humans could scare the bears, or make them think it's a sign of food and encourage them to areas that aren't suitable.

Quiz How much do you know about these icy hunters?

As well as tracking bears in their natural habitat, a 12-year-old polar bear called Charly is also taking part in hearing tests at the Seaworld marine park in America.

He's been trained to respond when he hears a computer-generated tone, in return for rewards of foods he loves like fruit, fish and fat!

Charly's trainer Mike Price said: "He very much enjoys the game. When I'm setting up equipment he gets really excited.

"This game works very well for him but is also helping science, so everyone's winning."

Bear reactions

So far, scientists have found the bears are much more sensitive to sound than we are.

Now they want to find out once and for all how bears in the wild are reacting to it.