The thorny issue of Irish hedgehogs

PERHAPS it’s a figment of my imagination, but there seem to be a lot of dead hedgehogs on the roads just now.

Hedgehogs have been around for a very long time but, when this little animal evolved its protective spines, the threats to it were very different from those it faces today. Hedgehogs, however, are not moving with the times.

Your average hedgehog has about 6,000 spines. Made of keratin, finger-nail material, each one lasts for about a year-and-a-half before it’s replaced by a new one. Muscles, just under the skin, raise the spines if the animal feels threatened and a flap of spine-covered skin is pulled down over the head. Another flap covers the anus so that the body is totally enclosed in a prickly ball. Baby hedgehogs are born in a bag so that their tiny spines don’t injure their mothers during delivery.

A rolled-up hedgehog is well protected from predators. Hogs have such confidence in their protective armour that they are not afraid of being observed. They will often ignore a person who approaches them and, during their nightly rounds, create a racket as they forage through leaf litter and vegetation searching for slugs and snails. Noisy eaters, they snuffle and snort constantly. Indeed, one of the best ways to find hedgehogs is to remain still and listen.

But the armoured defence has its limitations. It’s no deterrent to badgers, which can prise open the little spiky ball. Badgers are very partial to hedgehog flesh, so much so that the hogs generally leave an area as soon as they smell a badger. The other great enemy against which a spiny coat is no defence is the motor vehicle. Hedgehogs are active at night; caught in the headlights of an approaching car, and intimidated by its noise, the poor animal’s instinct is to roll into a ball. Ostriches are said to stick their heads in the sand when danger threatens. They don’t, but hedgehogs do, tucking their heads under their spiny coats. If the little bundle happens to be in the path of a wheel, there is no escape.

More male hedgehogs are killed on the roads than females because males travel more, not just in search of food, but also for encounters with receptive females. Both sexes, however, are extremely mobile.

Neither males nor females hold territories. Nor do they leave scent marks to warn off rivals. Instead, they seem to wander all over the place.

Your average male will travel about 3km in a night and its foraging area, or ‘home range’, is about 25 hectares in extent. In the course of a year, an individual is likely to range over a 100 hectares or more.

It has been suggested that there are hedgehog ‘accident black spots’, locations along roads where hedgehogs cross; people claim to find inordinate numbers of dead hedgehogs at these spots. This suggests that there are paths which hedgehogs use, the fatalities occurring where the paths meet roads.

But this does not square with what is known of hedgehog behaviour. Anti-social creatures, they tend to avoid encounters with each other and it seems unlikely that they would use common paths. Stand-offish attitudes might also explain why they seem to wander about so much; if a hog detects the presence of another individual, it may change the direction in which it is travelling. Only when a male detects the scent of a female in heat are hedgehogs likely to be sociable.

These little short-legged creatures can run remarkably fast, covering up to 40 metres per minute in a sprint. Few obstacles, apart from high walls, can block a hedgehog’s path.

If badgers are partial to hedgehog flesh, so were people long ago.

In all probability, hedgehogs were brought to Ireland as a source of food.

Introduced or not, this is one of Ireland’s most successful mammals. It is found in every county, although, fortunately, it has not reached our marine islands. If it did so, there might be disastrous consequences. In 1974, a gardener in the Uists brought a few hedgehogs from the Scottish mainland to help control the slugs which were eating his plants. In the absence of enemies and being able to hibernate during the winter, when food shortages and living conditions would make normal life impossible, the hedgehogs thrived. Their descendants now number in excess of 10,000. Wading birds, mainly redshanks dunlins and ringed plovers, nest on the Uists. The hedgehogs gorge themselves on the eggs of these ground-nesters and the numbers of these vulnerable birds have fallen drastically. Conservationists recommend that the hedgehogs be culled.

Meanwhile, in Ireland, somebody needs to knock some sense into our hedgehogs to get them to stop rolling up in front of cars.