Anglia Whipsnade Zoo

The snails became endangered in the 1990s after a on native species was introduced. So far the programme has returned more than 24,000 of the creatures.

The monkeys are on the Red List of Endangered species and there are estimated to be only 2,000 left in the wild.

The cameras allowed the zoo to learn more about the herd’s sleep patterns, social structure and interactions after dark.