African Pygmy Hedgehog

(ATELERIX SPP.)

Debbie Fry BSc(Hons) PG Cert

Introduction

The descriptive term ‘African Pygmy Hedgehog’ often refers to a mix of species within the Atelerix genus. This genus is native to Africa and includes four members, although in recent years, A. albiventris has been the focus of selective breeding for the pet trade due to its small size (Santana et al. 2010). African Pygmy hedgehogs are increasing in popularity as exotic pets, although many are being presented to veterinarians with diseases and husbandry-related disorders (Lennox, 2007). The following information therefore reviews captive husbandry, health and natural-behaviour considerations to inform protocol for captive African Pygmy hedgehogs. This, in turn, raises questions as to the welfare impact of captivity on this species.

Species Background

Hedgehogs comprise twelve species which are found in much of Africa, Asia and Europe. They are characterised by protective spines, an ability to roll into a tight defensive ball and a largely nocturnal, solitary nature (Heatley, 2005). Despite their wild status, African Pygmy hedgehogs are commonly encountered in the North American pet trade, although importation is highly controlled to limit potential disease risks (Heatley, 2005). The average weight and length of an African Pygmy hedgehog is 335g and 21cm respectively, and selective breeding is now responsible for several colour varieties (Santana et al. 2010).

In the wild, African Pygmy hedgehogs inhabit various dry-soil habitats, including grasslands and woodlands, with sheltered nests made of leaves or matted grass occupied daily for resting (Santana et al. 2010). They have well-developed sight, scent and hearing senses which allow prey to be located up to 4cm beneath ground-level (Santana et al. 2010). Although plant matter can be consumed, diet largely comprises invertebrates such as beetles, earthworms and slugs, alongside small vertebrate such as lizards and frogs (Santana et al. 2010). Plant-based cellulose is not efficiently digested; instead the external skeleton of insects is broken down into a source of dietary fibre (Dierenfeld, 2009).

Captive Husbandry

African Pygmy hedgehogs are best suited to housing with smooth walls and floors; these limit injury scope, are cleanable, filter light and diminish household noises (Banks et al. 2010). Wire cages are not recommended. Considering the wild African hedgehog has a 200-300m home-range (Santana et al. 2010), housing should be as large and well-ventilated as possible. This should include absorbent bedding such as newspaper and fleeces, replaced daily to limit infection risks, alongside boxes or shelters to simulate nests. Housing temperatures should be maintained at 25-30ºC to stop hibernation from occurring (Santana et al. 2010) which, due to reduced immune response, increases infection risk (Bouma et al. 2010).

Whilst hedgehogs often move slowly, they are capable of speed and climbing; particularly during the night or evening when they are most active (Santana et al. 2010). Housing enrichment which allows this behaviour, without injury or limbentrapment risk, is therefore ideal. Hiding places, tunnels, pots, straw or leaf provisions can be provided and rotated regularly to promote exercise, novelty and exploration. Natural materials are ideal, including wood bark or branches sourced from non-pesticide trees without signs of disease or damage, although these should be replaced frequently for hygiene purposes. Commercial wet and dry cat food (non-fish), mealworms and limited vegetable portions should be provided regularly: mealworms prevent malnutrition and dried foods limit dental disease. A water dish should be constantly available as some hedgehogs never adapt to bottle drinkers (Santana et al. 2010).

African Pygmy hedgehogs are a largely solitary species and therefore should be housed alone. Occasionally however, captive females will share housing without conflict, although signs of stress should be observed; this includes hissing and occasionally, screaming (Santana et al. 2010). By contrast, a relaxed hedgehog will lay its spines relatively flat to its body. Pregnant females should always be housed separately, and disruption to females with young should be minimal to reduce risks of desertion or cannibalism (Santana et al. 2010). Other behaviours to be aware of include self-anointing, whereby the hedgehog expels a saliva mix onto its spines. Although reasons for selfanointing are unknown, this appears to be related to contact with aversive substances and as such, may have defence origins (D’have et al. 2005).

Captive Health

The expected lifespan of wild African Pygmy hedgehogs is up to 4 years, although captive counterparts often exceed this age due to advances in veterinary care (Heatley et al. 2005). Captive hedgehogs however, are susceptible to various diseases including tumours, heart disease, wobbly hedgehog syndrome, musculoskeletal disorders and eye injury. Tumours are commonly diagnosed (Phair et al. 2011), and whilst advancing age is considered a risk factor, individuals from 1 month of age can be affected (Heatley et al. 2005). In general, 85% of hedgehog tumours are malignant and prognosis is poor (Heatley et al. 2005).

The disease described as wobbly hedgehog syndrome (WHS) is a progressive paralysis which in North America, occurs in approximately 10% of captive African hedgehogs (Graesser et al. 2006). Symptoms include loss of coordination and neurological signs, progressing to complete paralysis, with disease onset generally before 2 years of age. This is considered an inherited disease influenced by diet, husbandry or infectious agents (Banks et al. 2010). An emerging musculoskeletal disease causing degenerative spinal discs, which clinically resembles WHS, has also been identified; although disease onset tends to be later (Raymond et al. 2009). Other musculoskeletal diseases, often manifesting as lameness, can be a result of overgrown nails, foot infection, obesity, arthritis or fractures (Banks et al. 2010). Obesity is a common problem, as hedgehogs naturally have a low metabolic rate (Santana et al. 2010), yet captive individuals may be over-fed or have limited activity opportunity.

Corneal ulcers, or other eye injuries, also occur frequently in captive African hedgehogs, although vision loss does not appear to impact environmental navigation (Banks et al. 2010). Additionally, captive African hedgehogs are susceptible to various bacterial, fungal and viral infections, including ringworm and salmonella; the latter estimated to be carried by up to 28% of individuals (Santana et al. 2010). Symptoms may include weight-loss, poor skin health, respiratory problems or changes in faecal composition or colour, and a veterinarian should be consulted immediately if disease is suspected.

Further Considerations

The process of domestication occurs as many generations of a particular species are bred for certain traits, whilst being regularly handled by humans. For domestication to be successful, both humans and the species concerned must benefit (Robinson, 2011). A primary example is the domestic dog, who secured food and companionship in return for hunting and guarding. Despite mutual benefits however, the process of dog domestication took between 10,000-33,000 years (Wayne and vonHoldt, 2012). By comparison, hedgehog domestication began in the 1980s, and whilst humans may benefit from this relationship, mutuality is questionable.

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