A Leicestershire zoo is experiencing a baby boom in its rare monkeys unit.
The Pygmy marmoset is the smallest monkey in the world
The babies include pygmy marmosets which are the smallest monkeys in the world - an adult weighs approximately 125g and fits in a teacup.
Visitors to Twycross Zoo have been warned to look closely for the babies - they are only as big as a human thumb.
The zoo has the world's largest collection of primate species and is a major world player in global breeding programmes to aid species survival.
Susanne Boardman, from the zoo, said: "They're available for the public to see, you have to look carefully because the babies are clinging around the back and peaking out over the edges.
"I went down to see them this morning again and I must say they are very cute."
In the marmoset and tamarin world the father takes on the brunt of childcare duties, with the mother helping at feeding times, but generally the father does the rest of the day to day work, a zoo spokesperson added.
"The pygmys are endangered. We have tried to reintroduce them back into the wild because the numbers are decreasing," Amanda Jackson, primate keeper said.