The tiny pair were born to mum Humbug and dad Minty and are being looked after by the proud parents and sister Murray.

Keepers chose the minty names due to the brilliant silvery white colouring of the monkeys, who originate from the South American rainforests. The pair were born two months ago but are only now clearly visible to visitors who can see them as they take their first leaps away from mum and dad in their indoor and outdoor quarters, to the right of the otter pond.

The marmosets were only 2ins in size when born and when fully grown will reach about 8ins long, minus their tails. Keeper Carole Day said bringing up the pair is a family affair.

“The are a close-knit group and both dad and mum take their fair share of feeding and carrying and so does big sister as it is all part of her training for when she is a mum herself,” she said.

“The twins are already getting used to outdoors as they are carried out regularly by the family. You can even hear them screech as they are left out on a branch, but this is all part of growing up.”