London Zoo holds its annual weigh-in

Tortoise callipers and camel scales are put to good use at ZSL London Zoo, which is holding its annual animal weigh-in. While keepers put on a show for the cameras, it is important that the zoo keeps up-to-date size and weight information on its animals to compare them with animals in the wild and in other zoos, as well as to have an indication of which animals are pregnant.