After the first of the year, retailers and small businesses always face the daunting task of taking inventory of their stock. The London Zoo has an inventory to catalogue, too, but it’s a bit trickier for a very obvious reason: The inventory doesn’t stay still. And there’s a lot of inventory. The London Zoo on Thursday began its annual census among the more than 17,500 animals, birds, reptiles, fish, and invertebrates. IBTimes TV has the somewhat odd but quite intriguing report:

As the report said, some creatures are harder to count than others.

“The penguins and the meerkats aren’t too bad, but flocks of birds, especially in our free flight aviaries, they can be a little bit challenging, but this is about reconciling our records,” zoological director David Field told IBTimes TV.

“Every day the keepers come in and they check and count their animals and we just need now to make sure all of our data is correct, because it is not just about how many animals we’ve got–we also need to make sure who we have got.”

Zoos play a vital role in captive breeding and ensuring that future generations of wild creatures are preserved. A global database keeps track of the animals in captivity by responsible zoos.

The Associated Press offered more details:

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.

Counting inventory on a shelf sounds much easier, but admittedly, not nearly as exciting.