This is a Patagonia Cavy - Mara which is a large rodent from Argentina. The Adelaide Zoo has been very successful in a breeding program with around 6 babies born at different times throughout 2014. I was watching two of the babies for a while in the hope they would move into a better area to get a photo instead they dug a hole and escaped under the fence. As the keeper was just nearby I mentioned they had disappeared into the next area so he thanked me and raced off to recover and presumably try and make it more secure. Hopefully next visit I will be able to get the baby photo but in the meantime here is Mom or Dad who stood by watching the escape artists.