Black-tailed tree rat (Thallomys nigricauda)Order: Rodentia
Family: Muridae
Genus: Thallomys (acacia rats)
They live almost solely in camel thorn trees where they build large nests of grasses, twigs and leaves in hollows and forks. These nests present a huge fire hazard, for the trees. Also the weight of the nest (especially after rain) combined with the rats' secretions (acidic!) weaken overhanging branches at the fork and can cause them to break off.
Diet consists of everything an acacia can supply: leaves, pods, gum, but they also eat grasses, pods of other trees/plants, berries, roots and the occasional insect.
They are reported to live in colonies/groups but apparently not very much is known about the species in the wild.
They are indeed cute and it is said that they make nice pets. So unfortunately you can find them in specialised pet shops too. Well, in Europe you can.

But please don't try this at home, kids!