The Life of a Hedgehog

The hedgehog (Erinaceus europaeus) can be found where there is close proximity of grassland to woodland, scrub and hedgerow, e.g. at edge of woods, hedgerows in meadowland, or sand dunes with shrubs. They are virtually present in all lowland habitats where there is sufficient cover for nesting. A limiting factor in their distribution, particularly across Europe is the availability of suitable site and materials for nesting, particularly in the winter. Hedgehogs can be found all over the UK and Ireland however, and are a common sight in our woodlands. Hedgehogs are known for their main distinctive feature of several thousand sharply pointed spines. These completely replace hair on the upper surface of their body except for the face and a narrow patch on the skull. Their spines, which are about 22mm long are long lasting, irregularly replaced and used as a defence mechanism at the first sign of danger. Although their eyesight is poor, smell and hearing is acute enabling them to respond rapidly to danger, rolling up into a prickly ball - the head and all vital organs being protected by this unique adaptation. A hedgehog's whereabouts can be determined by its tracks (footprints). These are approximately 3.5 cm long & 2.5 to 3 cm wide, the length usually being measured without claws. The size of its tracks quoted here is an average however, and can differ according to the age, condition, development and even sex of the animal. The hedgehog moves only by walking, or at the most by fast walking, which is reminiscent of a slow trotting tread, so the hedgehog is only capable of a very slow pace. A hedgehog's main period of activity is at night, when they hunt. During the day they generally rest. They can be found resting in thickets, a pile of stones or in a nest of leaves. During their nocturnal rambles they gather insects and often hunt small vertebrates as well. A hedgehog exists almost entirely on ground living invertebrates but will take a small number of birds eggs and chicks. The only detailed study in Britain that covered a variety of habitats, showed that scarabeid beetles, caterpillars and earthworms formed 55% of their diet by weight. Food was found to be entirely caught and dealt with by the mouth. Interestingly, during this study, some truth was found in old folk tales, which suggested that hedgehogs carry fruit (particularly apples), on their spines ! Although some evidence was found for this, the validity of the story is disputed. During the winter months a large nest is built for hibernation. Food is collected in preparation for this event. The nest is used for up to 6 months, usually from October to April (the hibernation period). Sometimes a summer nest is built but usually only for breeding purposes. Hedgehog's deliver a litter of four to six young usually born in June, sometimes with a second litter later in the summer. Once a litter is born they put on weight rapidly as they begin to leave the nest after 22 days and live solitary lives thereafter. In order to survive winter they must become fully grown by hibernation in autumn. Later litters that hibernate at a sub-adult size are unlikely to survive the winter. Once the hibernation period is over the cycle begins again, resting in daylight and hunting at night in preparation for next winter's hibernation. This is the main activity of a hedgehog's life. Hedgehogs are particularly useful in the UK, as they are a predator of garden pests, such as slugs. They are often invited to gardens by food bowls ! The hedgehog is a fascinating mammal and as a nation we are lucky that they are so prevalent in our country.

Mike Ambrose