The Hedgehog

Words and images by Peter Hanscomb

The European hedgehog , Erinaceus europaeus is not only one of Britain’s favourite small mammals , it’s also one of the oldest , first evolving over fifteen million years ago. Once a common sight in our towns and villages the hedgehog in now under serious decline and threat from development and habitat loss and the use of modern pest control methods. This small spine covered nocturnal mammal is a regular unmistakable visitor to urban gardens and park-lands throughout the spring and summer. Widespread throughout the British mainland and most of western Europe , the European hedgehog is one of 17 species of hedgehog found worldwide.

The Hedgehog is around 20 – 26cm in length , and can weigh between 500g and 2Kg. A hedgehog must build up a reserve of body fat during autumn in order to survive the winter hibernation period . Any animal less than 500g at the beginning of hibernation is unlikely to survive the winter. The hedgehog is covered  in around 7000 quills or spikes , the animals main defence against predators. These are attached to a single muscle that can move the spikes in the direction of an aggressor.

The Hedgehog is known in the U.K. As the gardeners friend , in part because of it’s diet of garden pests such a slugs , snails and insect. It used to be considered a culinary delicacy by the British travelling community and baked in clay , thankfully this was a long time ago. It also features in British folklore, literature and British tradions. Probably the most famous example is Beatrix Potters The Tales of  Mrs Tiggy Winkle first published in 1906. Hedgehogs make an appearance at the mad hatters tea party in Alice in Wonderland and pass a striking resemblance to the Wombles of Wimbledon Common , a much loved series of books and children’s TV program from the 1970’s. Sega’s Sonic the Hedgehog made his debut in the gaming world in 1991 and still remains a firm favourite.

Reproduction 

Hedgehogs reach sexual maturity in their second year of life, and after this can breed every year until death. Reproduction occurs any time between April and September, but the period of greatest activity, ‘the rut’, occurs in May and June in Britain.Hedgehogs normally have only one litter of four to six babies per year. The baby hedgehogs or Urchins / hoglets are born after a 35 day pregnancy and arrive in the world blind and deaf. The mother raises the urchins in a maternity nest , normally leafs , under a hedgerow or in urban areas under a shed or outbuilding. The urchins are born with their first set of spines covered by a thin skin. As soon as they are born the spines start to come through the skin , by day 14 the eyes and ears have opened and at 8 weeks the urchins are ready to leave their mother and gain independence. The male hedgehog plays no role in raising the young and can be a danger to his own offspring .

Diet

Hedgehogs are formally classified as members of the mammalian order of Insectivora but in reality they are generalists feeders and their diet in the wild consists of a wide range of invertebrates, worms , beetles , slugs , caterpillars, earwigs and millipedes.They also eat a wide range of other insects and will infrequently take adavantage of carrion , frogs , baby birds, bird eggs and fallen fruit. In fact hedgehogs will eat almost anything found at ground level. Hedgehogs forage for food and will travel up to two miles in a night in order to find food.

For the urban hedgehog , this can be a real problem , roads provide a real danger , but perhaps the biggest hurdle is the constant development of  our suburban areas. Tidy gardens , impassable fences and walls and the use of garden pesticides all limit the options for the tiny forager. Perhaps one advantage the urban hedgehog has over its country cousin is the abundance of food left out deliberately in gardens for the hog visitor. Dog or cat food , certain fruits like apples and a small amount of mealworms can help supplement the hedgehogs diet. One word of caution, hedgehogs are lactose intolerant , milk contains lactose sugars that can irritate hedgehogs intestines causing diarrhoea. This in turn leaves the hedgehog dehydrated. Friends of the hedgehog should also refrain from leaving out bread for similar reasons. There are commercial products available to purchase from most good pet shops like Spikes hedgehog pellets. If you are leaving food out for hedgehogs in your garden its probably best to make a hedgehog  feeding station , a simple box with a small entrance the size of a can of beans . This should give the hedgehog a fair chance of getting to the food ahead of other garden visitors.

Predators

Badgers are the principal natural predator of hedgehogs in the UK, as they are the only creature strong enough to overcome the spiny defences. Hedgehogs have been shown to actively avoid areas where badgers are present, and in areas where badger densities are high, hedgehogs are likely to be less common. Badger populations have increased significantly in recent years but there is little evidence to suggest that badgers are the principal driver of our hedgehog decline. Foxes are known to occasionally hunt hedgehogs, though usually an adult hedgehog will be sufficiently protected by its spines. Whilst observing hedgehogs and foxes for the past couple of years , I have come to the conclusion that the fox poses little threat to a healthy hedgehogs and even see to accept the presence of each other , to the point that both see happy to feed in the same area at the same time. Tawny owls and golden eagles are also known to very occasionally hunt for hedgehogs in Britain.

Hibernation

Hedgehogs are one of the few mammals that are true hibernators. During hibernation hedgehogs are not really asleep, hibernation in a method of reducing energy consumption where the hedgehog will lower their body temperature to match their surroundings, slow their breathing and heartbeats to a minimum. The metabolic rate and energy consumption drops to around 4% of the level of an active animal by mid winter and the hedgehog enters a state of torpor. This allows them to save a lot of energy when their normal food sources are not available. In captivity where food is regularly available hedgehogs will not hibernate regardless of temperature.

Hedgehogs hibernate in a winter nest which is normally more substantial than their summer nests. It is built in undergrowth , in piles of wood or under hedges . the walls and base of the nest are made from compacted leafs with a wall thickness up to 180mm. The hedgehog collects leaves at night and then takes them to the nest site. The hedgehog will make a new nest every year and most will collapse shortly after the hedgehog emerges in the spring. As with most wildlife our habit of discarding modern day packaging is having a knock on effect with two local nests also including potato crisp packets included in the nesting material.

In the UK , hedgehogs usually hibernate from October/November through to March/April however the exact length of an individual hedgehogs hibernation will vary according to it’s size and physical condition , weather and the availability of food. Hibernation in the UK normally lasts for between 140 to 160 days but it’s not a continuous process and the hedgehog will wake up every 10 days or so for a few hours. During this brief time you may see a hedgehog out and about and individual hedgehogs may even move nesting sites during this period . so in actual fact a hedgehog only spends around 75 to 80 % of it’s time in deep hibernation. Hedgehogs lose between 20 to 30 % of their body mass during hibernation , for a normal adult this equals around 150 to 175 g of fat so its unlikely any adult entering hibernation with a body weight less than 500 g will survive the winter.

Conservation

Hedgehogs have some protection under Schedule 6 of the Wildlife and Countryside Act(WCA) 1981, which prohibits killing and trapping by certain methods, the Wild Mammals (Protection) Act 1996 and Appendix III of the ‘Bern’ Convention. In 2007, they were made a priority species as part of the former UK Biodiversity Action Plan.

The decline in hedgehog numbers in both urban and rural areas has many contributing factors . with modern farming practices leading to larger sized fields and a reduction to the number of hedgerows , the hedgehog is suffering from a lack of natural nesting sites. The use of pesticides is also reducing the number of invertebrates , a key part of a hedgehogs diet. The growth of the Badger population , the hedgehogs main natural predator has also had an effect on numbers.

In urban areas the problem with decline is mostly down to development. Secure garden fencing limits the area of foraging land available. Gardens are increasingly being lost to car parking and garden decking. Our desire for tidy well  manicured, managed gardens removes the scubby areas covered with brambles and reduces the nesting sites available. The use of pesticides and slug pellets also reduces the amount of natural food available to the hedgehog.

Help

Helping your local hedgehog population is really easy and relatively low cost . Out little friends need a large territory to roam and forage for food , so simple cut a small hole in the bottom of garden fence panels 140mm square can give hedgehogs a super highway. If possible provide cover , a simple few bushes with low growing foliage is perfect. Surprisingly a qood quality hedgehog house will often be taken advantage of by our little spikes friends, best to get one with a separate inner chamber, this helps keep inquisitive cats at bay. As far as food goes , definitely no bread or milk , instead cat or dog food with a high meat content , specialist hedgehog food and most important fresh water at ground level. Hedgehogs are great swimmers and like water so if you have a pond , think of making sure it has a shallow edge or ramp to help the hedgehog exit. Be careful when using a strimmer or lawnmower in the boarders of long grass , check for sleeping hedgehogs before you start.

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