IT was a story to melt the hardest of hearts – when newborn black howler monkey Diego's mother Molly died of heart problems just four days after his birth, he had to be hand-reared by keepers at Edinburgh Zoo.
In the absence of his mum, they gave him a cuddly toy monkey to snuggle up to and fed him milk every two hours, day and night.
Eight months on, all their tender loving care has paid off, as young Diego has been successfully reintroduced to the res
t of his family and his new step-mum.
Senior keeper of primates and koalas, Donald Gow, explained how Diego's gradual introduction had been achieved: "First of all we got a special cage built into the howler monkeys' enclosure so Diego could go and have protected contact with them. He could see, smell and hear them but they couldn't get at each other.
"Then we started giving him access into their enclosure without them in it so he could get used to the big enclosure whilst we observed him."
It was then time for Diego to be reintroduced to his family one at a time, starting with his big brother, Dargie.
Mr Gow said: "They were apprehensive to begin with but Dargie is only two so they bonded quite quickly and they're very playful now. Then we introduced him to his father, Keiko, and we've also acquired a new female, who's come to join the group as a breeding female, so that's his step-mother, Meryl."
Once they'd all got to know each other one-to-one, Diego was allowed to mix with the whole group for the first time about a month ago.
He is now receiving milk through a feeder just three times a day and eating root vegetables, leafy veg, willow and brambles, along with the other howlers.
Diego now spends all day mixing with the rest of the monkeys, although keepers still put him back in his own cage at night.
Mr Gow said the whole process had gone incredibly smoothly: "It can be very difficult to reintroduce animals. We've been lucky because howler monkeys are very laid back. The dad and step-mum have been very patient with him and he's playing a lot with Dargie. He's proving very popular."
The reintroduction proved such a success that Diego is already turning his back on his old friends – the keepers and the old soft toy he was once so close to.
Mr Gow said: "He does recognise us but there's no physical contact any more. And he doesn't have the toy any more. We took it out so he'd start bonding with the other monkeys. He did miss it at first, but he's very confident, so he gets over stuff like that quickly."