European hedgehog
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The European hedgehog (Erinaceus europaeus), also known as the West European hedgehog or common hedgehog, is a hedgehog species native to Europe from Iberia and Italy northwards into Scandinavia and westwards into Ireland.<ref name="Harris, S. 2008">Harris, S. & Yalden, D.W. (2008). Mammals of the British Isles: Handbook, 4th Edition. The Mammal Society, Southampton.</ref> It is a generally common and widely distributed species that can survive across a wide range of habitat types. It is a well-known species, and a favourite in European gardens, both for its endearing appearance and its preference for eating a range of garden pests. While populations are currently stable across much of its range, it is declining severely in Great Britain,<ref name=iucn/> where it is now Red Listed,<ref>Template:Cite web</ref> meaning that it is considered to be at risk of local extinction. Outside its native range the species was introduced to New Zealand during the late nineteenth and early twentieth centuries.
Description
The European hedgehog has a generalised body structure with unspecialised limb girdles.<ref name="Reeve 1994">Template:Cite book</ref> It appears brownish with most of its body covered by up to 6000 brown and white spines.<ref name="Morris, P. A. 2006">Morris, P. A. (2006). The New Hedgehog Book. Whittet Books, London.</ref> The length of head and body is ~Template:Cvt at weaning, increasing to Template:Cvt or more in large adults. It has an extremely short tail as an almost vestigial feature, typically Template:Cvt.<ref name="Harris, S. 2008 pp241-249">Harris, S. & Yalden, D.W. (2008). Mammals of the British Isles: Handbook, 4th edition. Mammal Society, Southampton. pp.241-249.</ref> Weight increases from around Template:Cvt at weaning to > Template:Cvt in adulthood. The maximum recorded weight is Template:Cvt, though few wild specimens exceed Template:Cvt even in autumn.<ref name="Reeve 1994"/> Adult summer weight is typically somewhat less than in autumn, with an average of around Template:Cvt and adult weights commonly as low as Template:Cvt.<ref>Template:Cite journal</ref> Males tend to be slightly larger than females, but sex differences in body weight are overshadowed by enormous seasonal variation.<ref name="Harris, S. 2008 pp241-249"/>
The European hedgehog is unlike any other creature across most of its range. Where it coexists with the northern white-breasted hedgehog (Erinaceus roumanicus), the two species are difficult to distinguish in the field, the latter having a white spot on its chest.<ref name=iucn/> It is probably the largest hedgehog species and is possibly the heaviest member of the order Erinaceomorpha.<ref name = "Wood">Template:Cite book</ref>
Colour variation
Leucistic or 'blonde' hedgehogs occasionally occur. Such specimens are believed to have a pair of rare recessive genes, giving rise to their black eyes and creamy-coloured spines; however they are not strictly speaking albino. They are extremely rare, except on North Ronaldsay and the Channel Island of Alderney, where around 25% of the population is thought to be blonde.<ref>Template:Cite journal</ref> True albino morphs of the hedgehog occur infrequently.<ref name="Morris, P. A. 2006"/>
Behaviour and ecology
The European hedgehog is largely nocturnal. It has a hesitant gait, frequently stopping to smell the air. Unlike the smaller, warmer-climate species, the European hedgehog may hibernate in the winter. However most wake at least once to move their nests.<ref>Template:Cite journal</ref>
Diet
The European hedgehog is an insectivore. Its diet consists largely of earthworms, as well as snails and slugs, beetles, ants, bees and wasps, earwigs, cockroaches, crickets and grasshoppers, butterflies and moths, and caterpillars and other insect larvae.<ref name=ADW>Template:Cite web</ref> Eggs of ground-nesting birds are also taken and carcasses may be foraged on. Hedgehogs may also eat lizards, snakes, frogs and small rodents.<ref name=ADW/> Plant matter appears to make up only a negligible part of the hedgehog's diet.<ref name=eulenberger>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
Breeding
The breeding season commences after hibernation. Pregnancies peak between May and July, though they have been recorded as late as September. Gestation is 31 to 35 days. The female alone raises the litter, which typically numbers between four and six, though the range is from two to ten. Studies have indicated that litter size may increase in more northern climes. The young are born blind with a covering of small spines. By the time they are 36 hours old the second, outer coat of spines begins to sprout. By 11 days they can roll into a ball. Weaning occurs at around six weeks of age.<ref>Template:Cite book</ref>
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A one-day-old newborn European hedgehog
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A female with one young
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Longevity and mortality
European hedgehogs may live to more than ten years of age, although the average life expectancy is three years. Starvation is the most common cause of death, usually occurring during hibernation. If alarmed, the animal will roll into a ball to protect itself. Many potential predators are repelled by its spines, but predation does occur. Remains of hedgehogs have been found in the stomachs of red foxes (Vulpes vulpes), European badgers (Meles meles) and pine martens (Martes martes). A large portion of these may be from hedgehog carcasses, especially roadkill. However hedgehogs tend to be absent from areas where badgers are numerous.
Eurasian eagle-owls (Bubo bubo) and golden eagles (Aquila chrysaetos) are the only regular avian predators of this species and may even prefer them as prey. The owl, after grabbing the hedgehog by its face, tends to skin the mammal's prickly back with its talons before consumption, resulting in several hedgehog backs being found around eagle-owl roosts and nests.<ref name= Konig>by Konig, Weick & Becking (2009). Owls of the World Yale University Press. Template:ISBN</ref> In Spain, reduction of European rabbit (Oryctolagus cuniculus) numbers due to rabbit haemorrhagic disease has made the European hedgehog one of the top preferred prey species for eagle-owls.<ref>Antonio Martínez, J., & Zuberogoitia, I. (2001). The response of the Eagle Owl (Bubo bubo) to an outbreak of the rabbit haemorrhagic disease. Journal für Ornithologie, 142(2), 204-211.</ref> Elsewhere, eagle-owls often prefer these hedgehogs to any other prey species, as the hedgehog can comprise up to 23% by number and 30.7% by biomass of eagle-owl prey remains.<ref name= Laursen>Laursen, J. T. (1999). Fødevalg hos Stor Hornugle Bubo bubo i Danmark. Dansk Orn. Foren. Tidsskr 93:141-144.</ref><ref>Leditznig, C., Leditznig, W., & Gossow, H. (2001). 15 Jahre Untersuchungen am Uhu (Bubo bubo) im Mostviertel Niederösterreichs-Stand und Entwicklungstendenzen. Egretta, 44: 45-73.</ref><ref name= Geidel>Geidel, C. (2012). Entwicklung neuartiger Schutzkonzepte für den Uhu (Bubo bubo) -Abschlussbericht 2012. Gutachten (DBU-Projekt).</ref> On the Swedish island of Gotland the golden eagle may take larger numbers of hedgehogs than any other prey owing to an otherwise low diversity of native land mammals, although the introduction of European rabbits has shifted the eagle's prey preferences there.<ref>Tjernberg, M. (1981). Diet of the golden eagle Aquila chrysaetos during the breeding season in Sweden. Ecography 4(1):12-19.</ref>
Nesting
European hedgehogs form nests where they spend much of their time. They construct three types of nest: breeding nests for birth and for protection of litters, day nests, which are used during the summer months, and winter nests or hibernacula, which are used for longer periods during winter months. Nests are often found under structures that can support them, such as roots or branches.<ref name=":1">Template:Cite journal</ref>
Distribution and habitat
The European hedgehog is native to Europe, with a global distribution extending from Ireland and the Iberian Peninsula eastwards through much of western to central Europe, and from southern Fennoscandia and the northern Baltic to north-west Russia. It is present also on Mediterranean islands (Corsica, Sardinia, Elba, Sicily), on most of the French Atlantic islands as well as on Irish and British islands (autochthonous and introduced).<ref>Mitchell-Jones, A.J.; Amori, G.; Bogdanowicz, W.; Krystufek, B.; Reijnders, P.J.H.; Spitzenberger, F.; Stubbe, M.; Thissen, J.B.M.; Vohralik, V.; Zima, J. (1999). The atlas of European mammals. Poyser London.</ref> It is an invasive exotic species in New Zealand and it has been suggested maybe to have been introduced to Ireland and many of the smaller islands where it occurs.<ref>Harris, S. & Yalden, D.W. (2008). Mammals of the British Isles: Handbook, 4th edition. Mammal Society, Southampton. pp.38-39.</ref>
Colonists took hedgehogs from England and Scotland to New Zealand on sailing ships from the 1860s to the 1890s, mainly as a biological control against agricultural pests or as a pet.<ref name=":0">Template:Cite journal</ref> Few survived the c. 50–100 days' voyage,<ref name=":0" /> but those that did had lost all their fleas. Animals found their first homes in the South Island, where their spread was helped by guards dropping them off at country railway stations. Hedgehogs were introduced to the North Island in the 1890s, but some were also transported from South Island between 1906 and 1911<ref name=":0" /> and from then on their numbers increased at an exponential rate. By the 1920s they had become so numerous that game-bird hunters blamed them for reduced bag sizes. Hedgehogs were declared noxious animals and a bounty of one shilling a snout was paid by regional authorities for several years. By the 1950s hedgehogs could be found over the whole country with the exception of the coldest wettest corner of the South Island and alpine areas of permanent snow. Nevertheless hedgehogs have been seen climbing New Zealand glaciers. Hedgehogs do not reach the same weight in New Zealand as in colder parts of Europe. With the milder winters New Zealand hedgehogs hibernate for only three months of the year so do not need to put on so much weight in autumn as their ancestors. In northern New Zealand many hedgehogs do not hibernate at all. One of New Zealand's pioneer hedgehogs probably had faulty teeth for this feature is found in about 50% of today's animals. Most New Zealanders welcome hedgehogs in their gardens since they relish slugs and snails. Conservationists are less happy, since hedgehogs compete for invertebrate food with native bush birds and prey on some rare insects, lizards and ground-nesting birds. As a result extensive hedgehog-control schemes are under way in some parts of the country, killing thousands of them. To judge by roadkill counts, North Island hedgehog numbers were at their highest in the 1950s. Since then, roadkill counts have fallen dramatically from about 50/100 km to less than 1/100 km.<ref>Template:Cite book</ref>
The European hedgehog is found across a wide range of habitat types, encompassing both semi-natural vegetation types and those areas that have been heavily modified by man. The range includes woodland, grasslands such as meadows and pasture, arable land, orchards and vineyards as well as within the matrix of habitat types found in human settlements. It prefers lowlands and hills up to 600m but is also locally present on mountains, exceptionally up to an altitude of 2000m (e.g. Alps and Pyrenees).<ref name="Mitchell-Jones, A.J. 1999 pp.38-39">Mitchell-Jones, A.J.; Amori, G.; Bogdanowicz, W.; Krystufek, B.; Reijnders, P.J.H.; Spitzenberger, F.; Stubbe, M.; Thissen, J.B.M.; Vohralik, V.; Zima, J. (1999). The atlas of European mammals. Poyser London. pp.38-39.</ref> Outside cultivated land it prefers marginal zones of forests, particularly ecotonal grass and scrub vegetation.<ref name="Mitchell-Jones, A.J. 1999 pp.38-39"/>
Hedgehogs are most abundant within the gardens, parks and amenity land close to or within human settlements.<ref>Template:Cite journal</ref> They are generally scarce in areas of marshes and moorland, probably because of a lack of suitable sites and materials for the construction of winter nests (or hibernacula), which have specific requirements.<ref name="Morris, P. A. 2006"/> In Finland they use pine-tree roots especially for nests in the winter.<ref name=":1" />
Conservation
Generally the hedgehog is widely distributed and can be found in good numbers where people are tolerant of their residence in gardens. The IUCN classifies the species as Near Threatened and currently the population as Stable. In some areas they are common victims of road kills and may be hunted by dogs, such as in Sardinia.<ref name=iucn/> On 28 August 2007, the new Biodiversity Action Plan included the European hedgehog on the list of species and habitats in Britain that need conservation and greater protection.<ref>Template:Cite news</ref><ref>UK List of Priority Species. Biodiversity Action Plan. ukbap.org.uk</ref>
In Denmark and Poland the European hedgehog is protected by law. It is illegal to capture or hurt them, but rehabilitation of unhealthy hedgehogs is accepted.<ref>Pindsvin Template:Webarchive. The Forest and Nature Department of DenMark</ref><ref>Dz.U. 2004 nr 220 poz. 2237. Internetowy System Aktów Prawnych. Isap.sejm.gov.pl (in Polish). Retrieved on 2012-12-29.</ref> It is protected in all European countries that have signed the Berne Convention on the Conservation of European Wildlife and Natural Habitats.
A low coverage assembly of the genome of Erinaceus europaeus was released by the Broad Institute in June 2006 as part of the Mammalian Genome Project.<ref>Template:Cite web</ref>
Status in Great Britain
Population size
An estimate of 36.5 million by Burton<ref>Burton, M. (1969). The Hedgehog: A Survival Book on Hedgehogs. London. Andre Deutsch.</ref> was based on extrapolating from a density of 2.5 animals/ha (one per acre), but this was based on limited data and is probably an overestimate. A more recent estimate of 1,550,000 in Great Britain<ref>Template:Cite web</ref> (England 1,100,000, Scotland 310,000, Wales 140,000) is more reliable but still has a high degree of uncertainty since it is based on very limited information about hedgehog density estimates for different habitat types.<ref name="Harris, S. 2008"/> Given this figure, and more firmly established rates of decline,<ref name="ptes.org">Roos, S., Johnston, A. and Noble, D. (2012) UK hedgehog datasets and their potential for long-term monitoring. BTO Research Report No. 598.</ref> it is now thought likely that there are fewer than a million hedgehogs in Great Britain.<ref>Vaughan, Adam (29 January 2013) "Hedgehog population in dramatic decline" Guardian Online Retrieved 4 September 2013.</ref> In the UK badgers are the main predator of hedgehogs<ref>Template:Cite web</ref> and also compete for some of the same foods.
Population status
In 2007 the hedgehog was classified a Biodiversity Action Plan priority species in Britain, largely in response to negative trends identified in national surveys such as Mammals on Roads survey,<ref>Template:Cite web</ref> run by People's Trust for Endangered Species (PTES), which found an annual decline in counts of road casualties of around 7% from 2001 to 2004.<ref>Bright, P., George, L. and Balmforth, Z. (2005). Mammals on Roads: development and testing the use of road counts to monitor abundance (draft v. 9). A report to PTES/JNCC.</ref><ref>JNCC "priority" species pages: Erinaceus europaeus.</ref> Historic data from the National Gamebag Census suggest a steady decline between 1960 and 1980.<ref>Tapper, S. (1992) An Ecological Review from Shooting and Gamekeeping Records. Game Heritage. Game Conservancy Ltd.Template:Dead link</ref> Evidence from a questionnaire in 2005 and 2006 also supported an ongoing decline, with almost half of ~20,000 participants in PTES' Hogwatch survey<ref>HogwatchTemplate:Dead linkSurvey Report, PTES and BHPS. Template:Webarchive</ref> reporting the impression that there were fewer hedgehogs than there had been five years earlier.<ref>Hof, A.R. (2009). A study of the current status of the hedgehog (Erinaceus europaeus) and its decline in Great Britain since 1960. PhD. Royal Holloway, University of London. Egham, Surrey, TW20 0EX, UK.</ref>
A review of the available survey data for the population trend of the hedgehog in Britain was undertaken by the British Trust for Ornithology (BTO) in a report commissioned by PTES and the British Hedgehog Preservation Society (BHPS).<ref name="ptes.org"/> This concluded that, at a conservative estimate, 25% of the British hedgehog population had been lost in a decade.<ref>Template:Cite web</ref> The report also highlighted the importance of long-term monitoring to provide datasets with sufficient power to allow the changes to the population to be identified. Currently, the most important monitoring programmes involved in collecting information about the status of the British hedgehog population are PTES' Mammals on Roads and Living with Mammals surveys, and the BTO Breeding Bird Survey and Garden BirdWatch survey.<ref>Battersby, J. (2005). UK Mammals: Species Status and Population Trends. A report by the Tracking Mammals Partnership No. 1, JNCC/Tracking Mammals Partnership, Peterborough.</ref> A recent review of these surveys now suggests that rural populations have declined by at least a half and urban populations by up to a third since 2000.<ref>Template:Cite web</ref>
Pest status
This species has become a serious pest in areas where it has been introduced outside of its native range. One such location is the Western Isles of Scotland, where introduced hedgehogs eat the eggs of ground-nesting waders such as common snipe, dunlin, common redshank and northern lapwing. It is also considered a pest in New Zealand, where it preys upon various native fauna,<ref>Template:Cite book</ref> including insects, snails, lizards and ground-nesting birds, particularly shore birds.<ref name="landcare">Template:Cite web</ref> As with many introduced animals, it lacks natural predators.
Attempts to eliminate hedgehogs from bird colonies on the Scottish islands of North Uist and Benbecula in the Outer Hebrides were met with international outrage. Eradication began in 2003 with 690 hedgehogs being killed. Animal-welfare groups attempted rescues to save the hedgehogs. By 2007 legal injunctions against the killing of hedgehogs were put in place. In 2008 the elimination process was changed from killing the hedgehogs to trapping them and releasing them on the mainland.<ref>Template:Cite news</ref>
In popular culture
- From the early 1950s until the 1980s, the hedgehog was sometimes seen as an unofficial symbol of NATO in numerous countries, as it represented a peaceful animal that bristles in defence.<ref>"THE HEDGEHOG: NATO'S LOST SYMBOL?", North Atlantic Treaty Organisation, published 20.10.2016, retrieved 16.02.2021.</ref>
See also
References
Further reading
- Macdonald, David W. & Priscilla Barrett (1993). Mammals of Europe. Princeton University Press. Template:ISBN.
- Warwick, Hugh (2010). A Prickly Affair: The Charm of the Hedgehog. Penguin. Template:ISBN.
External links
- Hedgehog Street UK conservation campaign
- ARKive Photographs and Videos
- WildlifeOnline Natural History of the European Hedgehog
- Hedgehog in the night (photographs) Template:Webarchive
- View the hedgehog genome on Ensembl
- Template:UCSC genomes
Template:Erinaceomorpha Template:Taxonbar Template:Authority control