Hedgehogs, (Erinaceus europaeus), occur in almost all areas of the UK, except some of the Scottish islands. They tend to be scarce in wetland areas, pine forests and the highlands, where suitable food and nesting sites are harder to find. They have adapted well to life in cities, and are common in many suburban areas.
Hedgehogs are easily recognised, as they are the only British mammal covered in spines. Each hedgehog has as many as 7,000 spines covering its back and sides, and when threatened, it curls into a ball, so that the spines offer protection. The chest and belly are covered in coarse grey-brown fur.
Beetles, caterpillars, earthworms, slugs and snails are the hedgehog's favourite food, but the diet is varied and they will also eat cereals, pet foods, and fresh meat. They can weigh up to 1.5kg. A male hedgehog heavier than this is overweight and needs to diet! Before hibernation, a hedgehog should weigh at least 0.5kg to survive the winter.
Hedgehogs are mostly nocturnal, and can travel long distances in their nightly forages for food, but they may remain in one nest for several days before moving on. The young are born between May and September, in litters of four or five. Hogs have been known to live for up to 14 years, but in the wild, most will die after two years.
Hedgehogs avoid the coldest times of winter by hibernating, usually between November and early April, depending on the weather. If it is warm enough and there is enough food, hedgehogs do not hibernate at all. During hibernation, the animal's body functions slow down, almost to a standstill. Heartbeat decreases from 1 90bpm to 20bpm and body temperature drops from 35°C to 1 0°C. This helps them conserve energy.
Hedgehogs build nests called hibernacula in which to overwinter. Favourite sites for these are under timber buildings, in piles of brushwood or leaves, or in compost heaps. If the weather changes during hibernation, or the animal is disturbed, it will wake and may move on to build a new nest.
Hedgehogs are the gardener's friend because they eat slugs and snails and other pests that damage plants. You can encourage hedgehogs into your garden by leaving piles of leaves and twigs around for them to nest in, or by making a purpose built shelter. Food should be put out at sunset, so that flies cannot lay eggs in it. If the food is not eaten by morning, it should be collected. A good hedgehog diet would include tinned pet food, chopped peanuts (not whole ones) or crunchy peanut butter, raw or cooked meat leftovers, muesli and a small amount of vegetables. They should not be fed on bread and milk if they are captive and cannot find other foods; this gives them diarrhoea .
Threats to hedgehogs
Most of us see more dead hedgehogs than live ones. Their natural defence of rolling up into a ball is, of course, useless against road traffic. The best way to reduce hedgehog road casualties is to drive more slowly, especially at night when hedgehogs are most active.
In the garden, hedgehogs may nest in long grass, and are sometimes injured by strimmers and lawnmowers, so check long grass before you cut it. Slug pellets can be deadly to hedgehogs too, but if you encourage hedgehogs into your garden they will eat the slugs. Bonfires can sometimes conceal a sleeping hedgehog, so check underneath before lighting.
Litter is dangerous to hedgehogs. They can become entangled in plastic rings that hold cans together, or become wedged in yoghurt pots or empty tins. Dispose of litter carefully and | squash all your tin cans before recycling them.
Despite all these hazards, the biggest threat to hedgehogs is habitat loss. Over the last 30 years, agriculture has favoured large fields and the habitats of the hedgehog, particularly hedges, have been lost. Pesticide usage also puts pressure on hedgehog populations. With more hedgehog-friendly gardens however, the mammal's future should be fairly secure.
Further information is available from the British Hedgehog Preservation Society, Knowbury House, Ludlow, Shropshire, SY8 3LQ.
The following books are available from good bookshops:
Morris, P. (1983) Hedgehogs, Whittet Books
Stocker, L. (1987) The Complete Hedgehog,
Chatto and Windus