An male orang-utan at Paignton Zoo in Devon has been working hard to preserve his species from extinction by making all three females at the zoo pregnant.
Bornean orang-utans Gambira, Chinta and Mali are expected to give birth in the next few months.
Demo, the father-to-be, is 10 years old and arrived from a German zoo in November 2007.
The primates are an endangered species. There are thought to be about 50,000 left in the wild, said the zoo.
Phil Knowling, from Paignton Zoo, said: "Demo has come to us and has helped to do the business.
"We've got three pregnant females here now and we're getting very close.
"It's an exciting time, it's important for the future of the species."
Mr Knowling said zoo staff were "crossing their fingers" that the births would be successful.
One of the females, Chinta will be a first-time mother, despite, at 18 years old, being the oldest of the group.
Two years ago Paignton Zoo sent out a "lonely hearts" advertisement to zoos around the world looking for a mate for her as she was prime breeding age.
It called for a "big, hairy, ginger male with terrific cheek pads".
Female orang-utans do not undergo the menopause, despite many living to more than 50 years of age.
The word orang-utan is derived from the Malay and Indonesian words orang, meaning person, and hutan which means forest, thus "person of the forest".