Primate keepers face a tricky task getting the world’s smallest monkey to bed as they attempt to round up 13 pygmy marmosets every evening.
Trainee keeper, Stephanie Sawyer, said: “Because they are so small it is a bit of a nightmare to get them all in as we have to count them.
“They are constantly tearing around and we usually end up counting an extra two or three, so it takes a few attempts every night.”
The group’s number has swollen with the arrival of two new babies in the last few days.
If you look very closely into their Primate House enclosure you may see the tiny babies clinging on to the back of an adult.
Baby pygmy marmosets are usually carried by the males of the group and only returned to their mother for feeding.