A baby wallaby is being hand reared in a rucksack by her keepers at Longleat Safari Park in Warminster after being found abandoned.

The youngster, who is thought to be around six months old, has been adopted by keepers Beverley Evans, Polly Yeo and Liz Grigg, who take it in turns to carry him around in a substitute pouch made from a specially adapted rucksack.

The baby - a red-necked wallaby - was rescued after being found cold and alone in the park.

"When we found him he was cold and very still and may well have spent the night out of the pouch, no one is sure why his mother abandoned him, but without our intervention he would definitely have died," said keeper Beverley Evans.

"Initially we had to feed him every two hours but now he feeds at four-hourly intervals and he's starting to take solids.

"At first it felt a little strange to be carrying this rucksack around wherever I went but after a while you do get used to it and I hardly notice the extra weight now - although in recent weeks he is beginning to get a lot more boisterous," she added.

At birth he weighed 20 grams and was little larger than a baked bean. He would have had to crawl through his mother's fur from the birth canal into the pouch where he began to suckle.

Volunteering to take over as surrogate mums has been a real labour of love for the keepers - especially with feeds every four hours day and night.

Beverley and her colleagues will have to keep up their role as adopted parent for up to 10 months until the youngster is fully weaned and ready to return to the rest of the 30-strong wallaby group.

"We fed him on a mixture of very rich milk substitute which is normally used for orphaned puppies and special vitamin supplements," said Beverley.

"As well as feeds we also have to ensure that he is kept clean and warm at all times and use a collection of pillow cases and babies nappies to line the inside of the rucksack to make it as comfortable as possible for him," she added.

Originally from Tasmania and Eastern Australia, the Red Necked Wallaby is a hardy species and very capable of surviving in the harsh British weather conditions. There are a number of small groups living wild in Derbyshire and Sussex which originated from animals which escaped from zoos in the 1930s.