letting nature back in

The ability of porcupines to survive in areas proximate to farmlands and suburbia is a double-edged sword for them, because their initial success results in their ongoing persecution by humans.

Porcupines come into conflict with us humans when they eat or damage crops and garden plants, damage fences and/or burrow under fences, chew on irrigation pipes or strip bark off trees. Additionally, their burrows can be obstacles to farm vehicles, and their abandoned burrows may harbour other animals that are also regarded as ‘problem animals’.

All of the above has led to porcupines being routinely killed, especially in farmlands where they have the status of vermin. Killing methods include shooting, poisoning, snaring, or setting baited traps to catch porcupines that are then clubbed or shot.

Despite all of this, a group of porcupines manage to survive on the margins of the commercial plantation behind our house. They shelter in burrows and at night they forage over significant distances, searching for a variety of plants and plant material. Being nocturnal, they visit our garden after dark in their ongoing quest for their favourite edible plants. To get in, they squeeze under the gate or even dig under our fence. On some visits they dig up and eat tubers or corms. Occasionally they also gnaw bark off certain trees.

As porcupines are nocturnal and very shy, I have not been able to photograph the porcupines that visit our garden regularly. This photo of a large porcupine is clipped from video footage taken by a borrowed trail camera that we set up in the plantation behind our garden

In addition to eating tubers, bulbs and roots, porcupines also eat shoots, stems and leaves of a variety of plants, tree bark, and fallen fruit and seedpods. In our garden the tubers and roots of Arum Lilies, Crocosmia, Leopard lilies and Freezias are among those enjoyed by porcupines. Sometimes their excavations can be impressive, but usually sufficient offsets and small corms and tubers are dispersed in the diggings so that the plants regenerate in the next season.

Our two dogs have learned to give visiting porcupines a wide berth and because of this “respect” they co-exist with the visiting porcupines without conflict.

A porcupine gnawed on the trunk of the Wild Honey-suckle tree (Turraea floribunda) in our garden about two years ago. The tree has recovered with no apparent adverse effects

The Wild Honey-suckle tree proceeded to flower the following spring. The parts of the trunk where the bark have been stripped off appear to have healed.

Porcupines are often regarded as wasteful feeders and their digging and burrowing is considered to be nothing short of damage. But ecologically speaking, in natural habitats porcupines can be seen as beneficial ecosystem engineers. Their diggings can accumulate water and organic material, including seed, and so have a positive effect on biodiversity, and their foraging habits can contribute to the regeneration of plants that propagate through corms and bulbs.

This video features clips taken using a trail camera of an adult porcupine drinking water, and even lying down as if to rest, on a hot night during March earlier this year. In the Eucalyptus plantation behind our garden, the thirsty trees mean that the local stream remains dry, even in the rainy season. To mitigate the effects, we have placed a water container, which we keep topped up with water, outside our garden providing the local wildlife with access to drinking water. 

Porcupines in South Africa, Hystrix africaeaustralis, are also known as Cape Porcupines. They are monogamous and usually produce a small litter once annually, with an average of only two young per litter. Breeding pairs live together and both parents contribute to raising and protecting the young, resulting in a relatively high survival level for the small number of babies. Sub-adults and juveniles, offspring from previous litters, often live in the same burrows as the breeding pair. Subordinate females in the group do not breed. The dispersal of sub-adults depends on population density, as well as on the dispersion and abundance of food sources.

Despite porcupines being widespread across much of South Africa, where levels of persecution are high, local extinctions are already happening. Their reproduction rates are slow and there is no room for complacency, even though porcupines are still relatively common. 

In addition to the persecution of porcupines in farmlands, porcupines are hunted for their meat and they are also common road-kill victims on our roads, and added to that, increasingly they are killed specifically for their quills.

In this still from trail camera footage, the quills on this porcupine can be clearly seen. When threatened a porcupine will raise its quills and so appear larger, and may defensively rattle its tail quills, making a noise that sounds a bit like shaking a large sheet of corrugated iron. To protect itself, a porcupine can also run backwards into its pursuer using its quills defensively. If contact is made the porcupine’s quills can become dislodged and embedded in face and body of its pursuer. It is not true that porcupines can “shoot” their quills

Unfortunately for porcupines, their quills have become popular for use in the fashion industry and in décor items. Some retailers may claim that quills sold have all been found after being naturally shed, but in fact animals are being killed specifically for the increasingly lucrative trade in quills, as described by Chevallier and Ashton (2006) in their report on this trade. 

 These pictures are randomly selected from Google images and provide examples of how porcupine quills are used in décor items

Next to the gnawed base of the tree in our garden, I placed all the quills we have found in our garden and the adjacent plantation. Despite a highly active resident group these are the only naturally shed quills we have found in the past 15 years. To keep up with the demand for quills in the retail trade, found quills are insufficient, and in any case are likely to be dirty or damaged, and consequently many animals are killed for their quills

Because many people are unaware that quills are obtained from porcupines that have been killed, with many being killed specifically for the quills trade, there have been campaigns to raise public awareness of the plight of porcupines in South Africa and asking consumers to avoid buying porcupine quill items. So if you are ever tempted to buy any such products, please, just say no.

This is a poster from the International Fund for Animal Welfare (IFAW) asking people not to buy products containing porcupine quills

Although more needs to be learnt about the habits, effects and distribution of porcupines, based on what is already known, several organisations are formulating recommendations for more sustainable ways of managing porcupines where they are a nuisance, and for more ethical and sustainable ways of harvesting their quills. They also want to raise awareness of the ecological value of the foraging and digging behaviour of porcupines as a “driver of diversity” (The Red List of Mammals of South Africa, Lesotho and Swaziland (2016, p.4).

But meanwhile back at the bottom of our garden, we were delighted to find that the trail camera had captured footage of a pair of juvenile porcupines apparently playing. At first they are seen approaching the water trough in the company of a sub-adult porcupine. After the sub-adult moves off, the clips show the juveniles playing together like two prickly kittens. Note that this footage has not been speeded up! In some of the sequences it looks as though the youngsters are practicing the advance-rapidly-in-reverse manoeuvre they may need to use defensively when they are older. In the meantime it all looks to be great fun!

Sources: 

Chevallier, Nick and Ashton, Belinda. 2006. A Report on the Porcupine Quill Trade in South Africa. This report was commissioned by IFAW (International Fund for Animal Welfare) http://media.withtank.com/23fd88d381/porcupine_quill_trade.pdf

Our Wild Neighbours. Living near porcupines. https://wildneighbours.com/living-near-porcupines/

The Red List of Mammals of South Africa, Lesotho and Swaziland. 2016. Hystrix africaeaustralis. https://www.ewt.org.za/reddata/pdf/Rodentia(10)/2016%20Mammal%20Red%20List_Hystrix%20africaeaustralis_LC.pdf

Van Aarde, Rudi. 1998. An Ecological Perspective of Reproduction in the Cape Porcupine. Transactions of the Royal Society of South Africa. 53(2): 237-243. Published online: 13 Apr 2010. http://www.ceru.up.ac.za/downloads/ecological_perspective_reproduction_porcupine.pdf

Posted by Carol