Erinaceus europaeus

FACTS AND FIGURES

Recognition: Unmistakeable, the only spiny British mammal.

Head/body length: 150-300mm, depending on age, tail about 10-20mm.

Weight: Up to 2kg, heaviest in autumn.

Lifespan: Up to 10 years (but this is exceptional). Over half die within their first year, and average life expectancy is 2-3 years in the wild.

Diet: Beetles, worms, caterpillars, slugs and almost anything they can catch, but little plant material. They can also take eggs and chicks of ground-nesting birds though rarely in large numbers and much less so than foxes and crows.

GENERAL ECOLOGY

The hedgehog is common in parks, gardens and farmland throughout mainland Britain and Ireland. It has also been introduced to many islands including Orkney, Shetland, Isle of Man and some of the Channel Islands. Hedgehogs prefer woodland edges, hedgerows and suburban habitats where there is plenty of food for them. Intensively farmed arable land is probably a poor habitat, as are moorlands and dense conifer forests.

Females have litters of 4-5 young (sometimes more), between April and September. Males do not assist in rearing them. Young born late often die, being too small to survive hibernation. They need to weigh at least 450g (1lb.) or they are not fat enough to last the winter.

HIbernation usually begins about November and ends around Easter, but is much affected by the weather. Hedgehogs normally wake up several times over winter and often build a new nest. In the spring they commonly spend a few days active then enter hibernation again during a cold snap. The winter nest ("hibernaculum") is made of leaves, tucked under a bush or log pile or garden shed, anywhere that offers support and protection. Hedgehogs travel about 1-2km each night, males more than females. They return to the same daytime nest for a few days then use another, perhaps returning to an old nest at a later date.

Hedgehogs carry several diseases, but none that are dangerous to humans. They carry a specific flea, which they sometimes pass to dogs, but do not carry the usual cat and dog fleas, which bite humans.

CONSERVATION

Hedgehogs are partially protected under the Wildlife & Countryside Act and may not be trapped without a licence from Natural England, the Countryside Council for Wales or Scottish Natural Heritage.

Hedgehogs may become locally scarce or even disappear, but nationwide extinction is unlikely. Nevertheless, hedgehogs appear to be in decline. The total population is unknown.

The biggest threat to hedgehogs is probably habitat loss, with the change from pastoral farming to arable crops, over the last 30 years. The use of chemicals in gardens and for intensive farming kills the creatures hedgehogs need for food and may also poison them directly.

Many are also killed on the roads.

Hedgehogs survive well in gardens, particularly assisted by food put out for them, as modern tidy gardens may not otherwise provide sufficient food. Gardens are also hazardous. Strimmers (cutters with a rotating strip of cord) cut back rank vegetation in the very places hedgehogs lie up during the day, causing serious wounds to the sleeping animals. Hedgehogs hibernate under garden bonfire heaps. These should always be turned over before being burnt. Hedgehogs swim well but easily drown in smooth-sided garden ponds, being unable to escape from them. Ponds (and swimming pools) should have a piece of chicken wire dangling into the water to help the animals climb out. Garden netting is also dangerous unless staked down tightly to avoid hedgehogs becoming entangled.

FREQUENT QUESTIONS

Are hedgehogs related to porcupines?

No, porcupines are rodents; hedgehog relatives include other insectivores such as shrews and moles.

Are hedgehogs becoming rarer?

Probably yes, because of habitat loss. However, there is no scientific proof because we have no accurate way of calculating hedgehog population sizes.

Is it wrong to feed them on bread and milk?

Yes, if they have nothing else to eat because it causes diarrhoea. However, wild ones have natural foods to dilute the effects and the extra food helps fatten them for winter. Pet foods, baby foods, milk substitutes and goats milk are all better diets but expensive and often not available. The best compromise is to dilute cow's milk at least 50/50 with water, but only for wild ones with access to other foods, not for captives.

Are slug pellets dangerous to hedgehogs?

Yes, and to other wildlife, children, and pets. Use carefully, under a stone slab where non-target animals cannot get them. Better still use beer traps or a safe substitute.

FURTHER INFORMATION

Harris, S. & Yalden, D.W. (2008) Mammals of the British Isles (4th edn.). The Mammal Society, Southampton.

Morris, P. (2006) The New Hedgehog Book. Whittet Books, London.

Sedgley, J. (1991) Hedgehogs in your Garden? The Mammal Society, London.

All available from The Mammal Society.