LONDON - It's tally time at London Zoo: 11 meerkats, 59 penguins, and two endangered Sumatran tigers that keepers hope will bring some cubs in 2013.
Zoo managers on Thursday started an annual cataloguing of its residents, from owls to otters, penguins to pygmy hippos. It's no easy task when there are more than 17,500 creatures to count, and the final tally could take weeks.
The census is required as part of the zoo's license terms, and the data is used for zoo management and international breeding programs for endangered animals.
Most animals in the zoo have microchips in their bodies, making counting a little less daunting. Fish and animals with camouflage properties -- like leaf insects -- are trickier, and the tiniest ones like ants are counted in colonies, not as individuals.
New additions to the zoo being counted for the first time included baby Ziggy, an endangered white-naped mangabey monkey, and Maxilla, a black and white colobus monkey.
The zoo also welcomed a pair of new Sumatran tigers -- male Jae Jae from a zoo in Ohio in the U.S. and female Melati, from Perth, Australia. The tigers were matched by an international breeding program to ensure a genetically-diverse population of animals, and will be meeting visitors in a newly-expanded enclosure in spring.
"They've met but they haven't been introduced to each other yet," said zoological director David Field. "We breed them in the zoo because they are running out of time in the wild."
There are now less than 400 of the big cats, native to Indonesia, according to the World Wildlife Fund.