Anyone remotely interested in local wildlife may already have noticed that hedgehogs seem to be fewer in numbers. While some may have assumed that the reason for not seeing them is simply a matter of being in the wrong place at the wrong time, David Wembridge's report 'The State of British Hedgehogs' confirms that hedgehog populations are indeed in the decline. They have, in fact, dropped by a quarter (25 per cent) in as little as 10 years. No-one is sure just why this is so, and there are many likely reasons, some of which will be dealt with later. Let's begin by taking a closer look at this lovely creature.
The British Hedgehog, Erinaceus europaeus, has the official common name of European Hedgehog. Widely spread across the continent, this lovely mammal is also often referred to as the Western European, Western, or Northern Hedgehog.
The hedgehog is the only spiny animal in Britain, and can not be mistaken for anything else. Growing up to between 20 and 30 cm (8 to 12 in) in length, hedgehogs can weigh between 1.5 and 2 kg (3.3 to 4.4 lb). Their upper side is covered in literally thousands of about 2.5 cm (1 in) long spines - a small hedgehog weighing just 600 g (1 lb 5 oz) has 5000 to 6000 spines - that are brown close to the body and gradually fade into white at the tips. They also have a roughly 2 cm (3/4 in) long tail, and 2 to 3 cm (3/4 to 1 2/10 in) long ears.
Rarely seen at full length - partly because they are hidden by the grey-brown, coarse fur covering the animal's chest, belly, legs, face and throat, and partly because hedgehogs tend to not extend them fully unless necessary - hedgehog legs are approximately 10 cm (4 in) long. This makes hedgehogs excellent short distance sprinters. Although they tend to amble about when foraging for food, they can reach speeds between 3.22 and 9.66 km/h (2 to 6 mph) if late for appointments.
Biology and Behaviour
Being predominantly nocturnal, the typically solitary hedgehog has comparatively poor sight. This lack of sight is, however, well compensated for by the animal's excellent sense of smell and above average sense of hearing.
While their sense of hearing is very well developed - the sound of an approaching worm would be perceived as loud - and partly used to detect both potential prey and danger, the sense section of hedgehogs' brains is taken up mostly by smell centres, indicating just how important this sense is to these creatures.
They use smell to recognise each other, detect potential predators (including humans - when the wind is coming towards them, they can smell people from several metres/ yards away), and - first and foremost - find food.
Constantly sniffing both the air and the ground, a hedgehog can smell a potential meal as far as 2.5 cm (1 in) below the surface. Hedgehogs also have a sense of taste, although they apparently do not care what their food tastes like - they will eat many insects other insectivores prefer to leave on their plates.
Quite noisy eaters (a hedgehog feeding under your bedroom window can be most alarming), hedgehogs have a fairly varied diet, including, among other things:
- Birds' eggs
- Small mammals
Beetles, caterpillars and earthworms are, however, favourite food items on this interesting hedgehog menu.
Living in temporary nests during the summer, hedgehogs spend most of the night foraging for food. If they sense approaching danger, they will roll up tightly into a ball, completely covering their soft undersides and heads. Few predators take the risk of attempting to break into this ball.
Their breeding season lasts from April right up to September, although most of the activity will take place during the warmer nights of May and June. After a gestation period of approximately 4 1/2 weeks, the females give birth to between 4 and 7 babies (there seems to be no official name for baby hedgehogs, although they are occasionally referred to as kits, pups, piglets, hoglets or hedgehoglet.
The hoglets are born blind, and their spines are just underneath the skin (nature's way of preventing injury to the mother during birth. Around two weeks later, their eyes open, and their spines begin to grow. A week later, they loose their baby teeth. At the age of four to five weeks, they leave the nest and learn to look after themselves.
Sadly, many of these babies die within the first few weeks of their life, often before they leave the nest. This means that, in spite of being capable of having two litters a year, most females will only raise two or maybe three babies a year. Those that do survive have an average expected life span of around three to five years, with a few fortunate individuals making it to the ripe old age of 10 years. This is, however, a rarity, mainly because hedgehogs have only one set of adult teeth and, once these teeth are worn down or lost with age, they can not feed properly and effectively starve to death.
With the approach of winter, hedgehogs prepare for hibernation by piling on as much fat as they can. They then retreat into a nest - called hibernaculum - made from grass, various plants and leaves, and go into a deep sleep. During this sleep, their metabolic rates drop drastically, allowing them to survive the cold, mostly insect-free winter months with no or very little food. They may wake up from time to time and move to another nest. Many hedgehogs will build at least two nests, so it is often possible to find many empty nests.
Threats and likely Causes for the Decline of Hedgehogs
Ironically, while designed by nature to help them survive the winter, hibernation is one of the biggest threats to a hedgehog's life. The reasons for this range from their inability to defend themselves against freezing temperatures, floods and the destruction of their nests by other causes to the dangers they expose themselves to by building these nests in piles of logs or leaves and other man-made or semi-man-made structures.
All too often, they are burnt together with garden rubbish, or on bonfires. This can be prevented by checking for hedgehogs before lighting up. Many of them become trapped in sheds, greenhouses and garages after building their nests in these inviting, warm and typically comparatively undisturbed places. Unable to get out, they can not find food and starve. Keeping doors closed at all times will stop them from getting in to begin with.
In addition, changes in agricultural practises and increasing urbanisation are continually reducing their natural habitat. Although hedgehogs tend to adapt fairly well to urban life, they do need places to hide, and well manicured, overly tidy gardens offer little in this respect. Making gardens hedgehog friendly by keeping at least part of them a little 'untidy' will give them somewhere to go.
Slug pellets and other pesticides also claim the lives of many, and carelessly discarded rubbish - especially those plastic rings around multi-packs of cans; plastic bags and cups; tins and yoghurt pots - poses a serious threat, as these inquisitive animals will scramble into them (particularly if smells promise a tasty morsel), get themselves stuck and end up either suffocating or starving.
Disposing of rubbish properly and keeping bin bags out of their reach (they will often tear bags open and climb into them to investigate, either ending up suffocating or being compressed when the bags are collected) will do much to prevent these unnecessary deaths.
Ponds, swimming pools, car inspection pits and fencing holes - in short, any deep holes with steep sides - are lethal traps for these gorgeous little creatures, as they are unable to clamber back out if they should happen to fall into them. Keeping one side of such features sloped offers them a chance to climb out.
Then, of course, there are cars. Growing numbers of roads and ever increasing traffic claim thousands of hedgehogs each year. What can be done? It really is quite simple. Chances are, drivers will meet hedgehogs during night travel, when traffic is typically at a low. Slowing down and being prepared to stop for an animal could prevent many roadside casualties - not only hedgehogs, but also badgers and other animals.
How YOU can Help
There are many ways to get involved in trying to stop the decline of hedgehogs. In addition to helping hedgehogs in your own garden, you could become a hedgehog champion; adopt a hedgehog and/ or learn how to care for hoglets. The sources listed below will provide additional ideas on how to successfully invite, care for and ultimately protect hedgehogs.