The North American tree porcupine seems like an easy-to-keep animal: it lives in North America, so there is no need for an indoor facility, it is a rodent, it feeds on any vegetables and fruits, and it is a slow-moving animal, it does not jump, it only climbs, therefore you can build it a simple enclosure. But if you start keeping this species, you can easily face problems you have not taken into account in advance. Let’s see how you can keep this species successfully.
North American tree porcupines (Erethizon dorsatum) are widespread in North America, live from Alaska to the northern part of Mexico, from the Atlantic Ocean to the Pacific Ocean. They are at home in variable habitats: coniferous forests, deciduous forests, grasslands and desert shrubs. So you would think you can keep them outdoors all year round in any climate, however, some zoos have experienced that tree porcupines can easily get pneumonia at winter and they do not tolerate a humid climate very well. Therefore, these zoos provide tree porcupines tempered, frost-free and dry shelters. Our experience in Miskolc Zoo, Hungary, is that tree porcupines really do not need tempered shelters in winter. Of course, there are some shelters in our enclosure, bedded regularly with dry hay and straw. But, as an example, our male is almost always on the top of the tree in their enclosure all year round: in rainy, snowy, or sunny weather, without any health problems. Nor do the tree porcupines of Blackpool Zoo, United Kingdom, have heated shelters, and these porcupines have been breeding very well for 30 years and usually live up to 20 years.
If you build an enclosure for tree porcupines, the most important aspect is that they climb very well, as they are ’tree’ porcupines. Our experience is that any smooth surface can prevent animal escapes. You can put metal or plastic plates on the inner side of the fence or use Plexiglas or other similar materials. Some zoos use an electric fence, but our experience is that it’s not a good solution, because if the animal bites the wire, its incisors can hitch on and the animal cannot release the bite. However, porcupines can get through under an electric wire – probably because their quills reduce the amperage of the fence –, but they cannot return to the ground, because the quills get caught in the wire.
As tree porcupines climb very well, it is necessary to furnish their enclosure richly with climbing trees. It is best to have a few live trees in the enclosure, however, you need to know that if you have only one or two trees, porcupines will destroy these very soon. Tree porcupines are mainly nocturnal, but I see that this varies by individual. Our male sits on the top of a tree during daytime, and comes down in the late afternoon or early evening. But our female is active throughout the day and as porcupettes learned this from their mother, they are very visitor-friendly animals, unlike the male.
Based on the experience of different zoos, the main difficulty in keeping tree porcupines is that they are sensitive to intestinal parasites. I think that the problems mentioned above – as pneumonia and other illnesses – originate in the following: tree porcupines weakened by parasites are more vulnerable to illnesses. In a previous period our porcupines also had intestinal parasites. We began an intensive course of deworming, and now we use vermifuge every quarter of a year. We use Noromectin paste (the active ingredient is Ivermectin) and Ferdocat (Fenbendazole) in 1:30 ratio. Of course, feeding also affects the incidence of parasites. Although it is not scientifically proven yet, but it seems that if tree porcupines eat the needles and bark of pines regularly, the incidence of parasites is lower. Based on the feeding of tree porcupines in Blackpool Zoo, we think that the etheric oils and resin of coniferous trees can help to hold the intestinal parasites on a low level. But animals are choosey, while our animals eat scots pine (Pinus sylvestris), they do not touch Norway spruce (Picea abies). Since we started the intensive deworming course and feed parts of coniferous trees regularly, problems with parasites have practically ended.
Apart from giving them pine, feeding tree porcupines is not a difficult thing. You can give similar food to these animals as to crested porcupines or other large rodents: vegetables, fruits, seeds and leaves of deciduous trees. According to literature, tree porcupines chew bones and shed antlers, and they gain minerals from salt (for example from along the roads at winter), therefore you can offer these, and the animals can decide to consume these or not. Although we don’t see tree porcupines drink, but fresh, clean water should be available at all times.
Tree porcupines are solitary animals in the wild, but you can keep several animals together in one enclosure without any problems. Before giving birth, a female can become aggressive towards her previous offspring, she will chase it out from her shelter, but the offspring can stay in the enclosure if it can find another shelter for itself. We have also seen some cases when the female let the one-year old porcupette suckle too.
Tree porcupines can also be kept together with other species in a mixed species exhibit. For example, in ZOOM Erlebniswelt Gelsenkirchen, Germany, tree porcupines live together with North American beavers (Castor canadensis). Other zoos keep tree porcupines successfully with striped skunks (Mephitis mephitis), raccoons (Procyon lotor) and prairie dogs (Cynomys sp.). In Tierpark Berlin, Germany, a tree porcupine was kept with a crested porcupine (Hytrix sp.) together to demonstrate the parallel evolution of quills in mammals. Furthermore, I think that tree porcupines can be kept together with other North American species as turtles, birds, squirrels and other animals.
I hope that our experience shows that, with only a little attention, it is relatively easy to keep this interesting and amazing rodent species successfully.