How many scorpions? London Zoo does critter count

Today more than 650 species were counted in London Zoo's annual animal count. The annual count is a legal requirement for all British zoos, and it's also a useful tool for monitoring animal conservation efforts.

"We have to tell the zoo licensing authorities exactly how many animals we have," said zoological director David Field, standing next to the manmade otters' pond. "It's not just the number of animals, it's who we've got, because many of our animals are individually identifiable." Many of the animals are easy to count, such as the giraffes; there's only a few of them. However, some tasks are much more difficult, such as counting the population of over 600 cockroaches, as well as determining if it has grown since last year. Piranhas are also very difficult to count, not just because of their strong jaws and impressive teeth, but because of their speed in the water. "They can be quite tricky because they move around the tank very fast," said zookeeper Tony Dobbs. "It can be a nightmare to count 20 fish. But to be honest, they're not as dangerous as people think, as long as they're well fed." He said keepers are cautious, nonetheless, about getting too close to the Amazon fish during the counting process. "We tend to avoid putting too much flesh into the tank, just in case." With some species, such as the leafcutter ant, zookeepers are required to make an estimate as counting these tiny critters would prove too difficult.