Staff at London Zoo have begun the mammoth task of counting every animal in their annual stocktake.

The task is not too arduous for meerkat keepers but for other animal handlers the inventory could take up to four weeks.

Staff in the aquarium have to head-count more than 4,700 fish while bug keepers have to tally-up thousands of tiny insects.

Recent additions to the zoo's population will be included in the census. A baby western lowland gorilla will be counted for the first time.

The male, who was born in October but is yet to be named, was the first gorilla to be born at the zoo in 20 years.

Other new additions to the inventory include two golden-head lion tamarins, two two-toed sloths and hundreds of tiny baby seahorses.

It is the first time the zoo's penguins will not be included in the count. The birds are in the process of being sent to Whipsnade Zoo while a new enclosure is built for them.

With births and deaths each year, the compulsory annual head count is vital for keeping tabs on the zoo's inhabitants.

The last inventory found there were more than 16,000 residents of the zoo made up of 726 different species.