Tokyo's Tama Zoo was placed on high alert after an orang-utan broke free of its pen and captured a young zookeeper.

Fortunately it was not the real thing but a dramatic re-enactment of an emergency drill with the lead ape character played by a local staff member in an orange fur suit.

Other staff members, with police and ambulance crews on standby, played their part with hard-hat helmets, wielding sticks and nets in an attempt to capture the berserk "primate".

The orang-utan finally fell, and very melodramatically, to a fake tranquilliser gun, much to the worry of watching children who couldn't work out if the drill was the real thing or not.

This is an annual event that prepares Tokyo Zoo's keepers for all the risks involved with keeping wild and sometimes irate animals.

Nearly 100 zoo officials participated in the drill which every year features different escaped animals such as gorillas, lions and even rhinos.

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