A childless female monkey has found a way to satiate her maternal drive — adopt a baby from another species, zookeepers report today.

The mother, a golden-headed lion tamarin named Maternal Juanita, lives at the ZSL London Zoo. She took a liking to her neighbor's baby — an emperor tamarin — just weeks after it was born.

Now the surrogate mum can be seen jumping around zoo exhibits with the 2-month-old baby on her back. The emperor tamarin's grey body and white moustache stand out against its "mother's" fiery orange mane. The baby tamarin is already showing signs of an adult's signature white moustache. In fact, the animals are thought to have been named after the Emperor of Germany, Emperor Wilhelm II, due to their long, white moustaches.

"Juanita has never had a baby before so it seems like her mothering instinct has just kicked in this time around," said Lucy Hawley, a senior zookeeper at the zoo. "Who knows what animal she'll be carrying around next?"

Emperor tamarins, native to South America, are usually raised by their fathers who carry them until they are old enough to fend for themselves.

Despite the monkey mix-up, there does not seem to be any hard feelings between Juanita and her neighbor – the biological parent of the emperor tamarin.

"At first the father of the emperor tamarin baby was a little nervous about Juanita — but now they all seem to get along just fine," Hawley said.