Cape Porcupines (Hystrix africaeaustralis) are nocturnal rodents, the largest rodents in southern Africa. They are occasional visitors to Meadowridge Common where they forage at night for bulbs, corms and tubers (the nutrient-packed underground storage organs of plants). During the day they shelter in burrows or caves on the slopes of Table Mountain, visiting the suburbs and farmlands at night, often finding their way through stormwater drains and along road culverts. They usually forage alone or in small family groups, communicating with high pitched calls, grunts and quill rattling. On average, they live for about 10 years in the wild, raising one litter of up to three young each year.
Porcupines are covered in coarse, long, black hair interspersed with cylindrical, needle-sharp, black-and-white quills that grow up to 30 cm long on the sides of the porcupine. There is a crest of longer, thinner, more flexible spines that runs from the head down its back. Their quills are modified hairs and will grow back if they fall out. They normally lie flat but can be rapidly erected, making the porcupine appear twice its normal size. If this display doesn’t deter its assailant, the porcupine can charge backwards and sideways and drive home its quills which are easily detachable. They cannot shoot their quills.
You may find evidence of porcupine activity on the Common. Sometimes their footprints can be seen in damp sand, or you will find a discarded black-and-white quill, or a few characteristic lumpy fibrous droppings. They leave distinctive funnel-shaped “foraging pits”, and discarded pieces of the bulbs they dig up. Their enthusiastic digging traps water and organic matter, and facilitates the germination and distribution of seeds and bulbils (small, asexual reproductive structures on many bulbous plants). They are thus important ecosystem engineers in the fynbos.
The bulbs of members of the Iridaceae family such as Watsonia, Babiana, Moraea and Romulea are their staple food source in the fynbos, as are the tubers of the arum (Zantedeschia aethiopica). Porcupines have remarkable defences against the toxins contained in some bulbs, like the Cape Tulip (Moraea collina) which is deadly poisonous to humans and domestic livestock if eaten. The bulbs contain cardiac glycosides that disrupt the cardiovascular, nervous and gastrointestinal systems of most animals. Somehow the digestive systems of the porcupines (and mole-rats too) can neutralize toxins. They can also cope with the microscopic, needle-like calcium oxalate crystals in arums that cause pain, swelling and choking in other animals.