Hedgehogs [1] Temporal range: | |
---|---|
European hedgehog | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Eulipotyphla |
Family: | Erinaceidae |
Subfamily: | Erinaceinae G. Fischer, 1814 |
Type genus | |
Erinaceus | |
Genera | |
A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are seventeen species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introduction. There are no hedgehogs native to Australia and no living species native to the Americas. However, the extinct genus Amphechinus was once present in North America.
Hedgehogs share distant ancestry with shrews (family Soricidae), with gymnures possibly being the intermediate link, and they have changed little over the last fifteen million years. [2] Like many of the first mammals, they have adapted to a nocturnal way of life. [3] Their spiny protection resembles that of porcupines, which are rodents, and echidnas, a type of monotreme.
The name hedgehog came into use around the year 1450, derived from the Middle English heyghoge, from heyg, hegge'hedge', because it frequents hedgerows, and hoge, hogge'hog', from its piglike snout. [4] Another name that is used is hedgepig. [5]
Hedgehogs are easily recognized by their spines, which are hollow hairs made stiff with keratin. [6] Their spines are not poisonous or barbed and, unlike the quills of a porcupine, do not easily detach from their bodies. However, the immature animal's spines normally fall out as they are replaced with adult spines. This is called "quilling". Spines can also shed when the animal is diseased or under extreme stress. Hedgehogs are usually brown, with pale tips to the spines, though blonde hedgehogs are found on the Channel Island of Alderney.
Hedgehogs roll into a tight spiny ball when threatened, tucking in the furry face, feet, and belly. [6] The hedgehog's back contains two large muscles that direct the quills. Some light-weight desert hedgehog species with fewer spines are more likely to flee or attack, ramming an intruder with the spines, rolling up only as a last resort.
Hedgehogs are primarily nocturnal, with some species also active during the day. Hedgehogs sleep for a large portion of the day under bushes, grasses, rocks, or most commonly in dens dug underground. All wild hedgehogs can hibernate, though the duration depends on temperature, species, and abundance of food.
Hedgehogs are fairly vocal, with a variety of grunts, snuffles and/or squeals.
They occasionally perform a ritual called anointing. [7] When the animal encounters a new scent, it will lick and bite the source, then form a scented froth in its mouth and paste it on its spines with its tongue. Some experts believe this might serve to camouflage the hedgehog with the local scent, and might also lead to infection of predators poked by the spines. Anointing is sometimes also called anting after a similar behavior in birds.
Like opossums, mice, and moles, hedgehogs have some natural immunity against some snake venom through the protein erinacin in their muscles, though in such small amounts that a viper bite may still be fatal. [8] In addition, hedgehogs are one of four known mammalian groups with natural protection against another snake venom, α-neurotoxin. Developing independently, pigs, honey badgers, mongooses, and hedgehogs all have mutations in the nicotinic acetylcholine receptor that prevent the binding of the snake venom α-neurotoxin. [9]
The sense of smell has been little studied in the hedgehog, as the olfactory part of the mammal brain is obscured inside the neopallium. Tests have suggested that hedgehogs share the same olfactory electrical activity as cats. [10]
Although traditionally classified in the abandoned order Insectivora, hedgehogs are omnivorous. They feed on insects, snails, frogs and toads, snakes, bird eggs, carrion, mushrooms, grass roots, berries, and melons. [6] Afghan hedgehogs devour berries in early spring after hibernation.[ citation needed ] Hedgehogs have been observed eating cat food left outdoors for pets, but this may not be a proper food for hedgehogs in captivity.[video:1]
When a hedgehog hibernates, its normal 30–35 °C (86–95 °F) body temperature decreases to 2–5 °C (36–41 °F). [11]
Hedgehog gestation lasts 35–58 days, depending on species. The average litter is 3–4 newborns for larger species and 5–6 for smaller ones. As with many animals, it is not unusual for an adult male hedgehog to kill newborn males.
Hedgehogs have a relatively long lifespan for their size. In captivity, lack of predators and controlled diet contribute to a lifespan of 8–10 years depending on size. In the wild, larger species live 4–7 years (some recorded up to 16 years), and smaller species live 2–4 years (4–7 in captivity). This compares to a mouse at 2 years and a large rat at 3–5 years.
Newborn hoglets are blind, with their quills covered by a protective membrane which dries and shrinks over several hours, [12] and falls off after cleaning, allowing the quills to emerge. [13]
The various species have many predators: while forest hedgehogs are prey primarily to birds (especially owls) and ferrets, smaller species like the long-eared hedgehog are prey to foxes, wolves, and mongooses. Hedgehog bones have been found in the pellets of the Eurasian eagle owl. [14]
In Britain, the main predator is the European badger. European hedgehog populations in the United Kingdom are lower in areas with many badgers, [15] and hedgehog rescue societies will not release hedgehogs into known badger territories. [16] Badgers also compete with hedgehogs for food. [17]
The most common pet species of hedgehog are hybrids of the white-bellied hedgehog or four-toed hedgehog (Atelerix albiventris) and the smaller North African hedgehog (A. algirus, pygmy hedgehog). [18] Other species kept as pets are the long-eared hedgehog (Hemiechinus auritus) and the Indian long-eared hedgehog (H. collaris).
As of 2019 [update] it is illegal to own a hedgehog as a pet in four US states including Hawaii, Georgia, Pennsylvania, and California, [19] as well as New York City, Washington, DC and some Canadian municipalities, and breeding licenses are required. No such restrictions exist in most European countries with the exception of Scandinavia. In Italy, it is illegal to keep wild hedgehogs as pets. [20]
In areas where hedgehogs have been introduced, such as New Zealand and the islands of Scotland, the hedgehog has become a pest, lacking natural predators. In New Zealand it has decimated native species including insects, snails, lizards and ground-nesting birds, particularly shore birds. [21]
Eradication can be troublesome. Attempts to eliminate hedgehogs from bird colonies on the Scottish islands of North Uist and Benbecula in the Outer Hebrides were met with international protest. Eradication began in 2003 with 690 hedgehogs killed, though animal welfare groups attempted rescues. By 2007, legal injunctions prohibited the killing, and in 2008, the elimination process was changed to trapping and releasing on the mainland. [22]
In 2022, it was reported that the hedgehog population in rural Britain was declining rapidly, down by 30%-75% since 2000. [23]
Hedgehogs suffer many diseases common to mammals, [24] including cancer, fatty liver disease, and cardiovascular disease.
Cancer is very common in hedgehogs. The most common is squamous cell carcinoma, which spreads quickly from bone to the organs, unlike in humans. Surgery to remove the bone tumors is impractical.
Fatty liver and heart disease are believed to be caused by bad diet and obesity. Hedgehogs will eagerly eat foods high in fat and sugar, despite a metabolism adapted for low-fat, protein-rich insects.
Hedgehogs are also highly susceptible to pneumonia, with difficulty breathing and nasal discharge, [25] caused by the bacterium Bordetella bronchiseptica. [26]
Hedgehogs uncommonly transmit a fungal ringworm or dermatophytosis skin infection to human handlers and other hedgehogs, caused by Trichophyton erinacei, a distinct mating group among the Arthroderma benhamiae fungi. [27]
Hedgehogs can suffer from balloon syndrome, a rare condition in which gas is trapped under the skin from injury or infection, causing the animal to inflate. The condition is unique to hedgehogs because their skin is baggy enough to curl up. [28] In 2017 the BBC reported a case of a male hedgehog "almost twice its natural size, literally blown up like a beach ball with incredibly taut skin". [29] [30] At Stapeley's Wildlife Hospital, vet Bev Panto, said, "I have seen three or four of these cases and they are very strange every time and quite shocking ... When you first see them they appear to be very big hedgehogs but when you pick them up they feel so light because they are mostly air". [28] The British Hedgehog Preservation Society advises:
There is no single cause for this condition. The air can be removed by incising or aspirating through the skin over the back. Antibiotic cover should be given. This may be associated with lung/chest wall damage or a small external wound acting like a valve or a clostridium type infection. [31]
As with most small mammals living around humans, many are run over as they attempt to cross roadways. In Ireland, hedgehogs are one of the most common mammalian road fatalities. Between April 2008 and November 2010 on two stretches of road measuring 227 km and 32.5 km there were 133 recorded hedgehog fatalities. Of another 135 hedgehog carcasses collected from throughout Ireland, there were significantly more males than females collected, with peaks in male deaths occurring in May and June. Female deaths outnumbered males only in August, with further peaks in female deaths observed in June and July. It is suggested that these peaks are related to the breeding season (adults) and dispersal/exploration following independence. [32]
Domesticated hedgehogs can get their heads stuck in tubes such as toilet paper tubes, and walk around with them. Some owners call this "tubing" and promote the behavior, providing a tube cut lengthwise to allow the hedgehog to remove it. Some hedgehogs intentionally wear tubes for hours. [33]
Hedgehogs are a food source in many cultures. They were eaten in Ancient Egypt and some recipes of the Late Middle Ages call for hedgehog meat. [34] They are traded throughout Eurasia and Africa for traditional medicine and witchcraft. In the Middle East and especially among Bedouins, hedgehog meat is considered medicine against rheumatism and arthritis. [35] Hedgehogs are also said to cure a variety of disorders from tuberculosis to impotence. In Morocco, inhaling the smoke of the burnt skin or bristles supposedly remedies fever, impotence, and urinary illnesses; the blood is sold as a cure for ringworm, cracked skin and warts, and the flesh is eaten as a remedy for witchcraft. [36] Romani people still eat hedgehogs, boiled or roasted, and also use the blood and the fat as a medicine. [37]
In 1981, British publican Philip Lewis developed a line of Hedgehog Flavoured Crisps, whose taste was apparently based on the flavourings used by Romani to bake hedgehogs. [38] [39] As they did not contain any actual hedgehog product, the Office of Fair Trading ordered him to change the name to Hedgehog Flavour Crisps. [40]
Subfamily Erinaceinae (hedgehogs) [1]
In worldwide folklore, hedgehogs are associated with intelligence and wisdom (Asia, Europe), and magic (Africa). [41]
The European hedgehog, 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 the British Isles. 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 where it is now Red Listed, 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.
Erinaceidae is a family in the order Eulipotyphla, consisting of the hedgehogs and moonrats. Until recently, it was assigned to the order Erinaceomorpha, which has been subsumed with the paraphyletic Soricomorpha into Eulipotyphla. Eulipotyphla has been shown to be monophyletic; Soricomorpha is paraphyletic because both Soricidae and Talpidae share a more recent common ancestor with Erinaceidae than with solenodons.
The domesticated hedgehog kept as a pet is typically the African pygmy hedgehog. Other species kept as pets include the long-eared hedgehog and the Indian long-eared hedgehog.
The long-eared hedgehog is a species of hedgehog native to Central Asian countries and some countries of the Middle East. The long-eared hedgehog lives in burrows that it either makes or finds and is distinguished by its long ears. It is considered one of the smallest Middle Eastern hedgehogs. This hedgehog is insectivorous but may also feed on small vertebrates and plants. In captivity they can live for over 7 years.
The Amur hedgehog, also called the Manchurian hedgehog, is a hedgehog similar to the European hedgehog in appearance and behaviour, although it is more lightly coloured. It is native to Amur Oblast and Primorye in Russia, Manchuria in China, and the Korean Peninsula. Like other hedgehogs, it uses scent and hearing while looking for prey, and the name "hedgehog" refers to the pig-like grunts it makes as it forages.
Brandt's hedgehog is a species of desert hedgehog native to parts of the Middle East and Central Asia. Its common name derives from its having first been described by Johann Friedrich von Brandt, a director of the Zoological Department at the St Petersburg Academy of Sciences.
The Indian hedgehog is a species of hedgehog native to India and Pakistan. It mainly lives in sandy desert areas but can be found in other environments.
The Indian long-eared hedgehog is a small species of mammal native to northern India and Pakistan. It is insectivorous and nocturnal.
The four-toed hedgehog, also known as the African pygmy hedgehog, is a species of hedgehog found throughout much of central and eastern Africa.
Erinaceus is a genus of hedgehog from the family of Erinaceidae. There are four main species of Erinaceus. The range is all across Europe, throughout the Middle East, parts of Russia, and extending to northern China and Korea. The European hedgehog has been introduced to New Zealand.
The North African hedgehog or Algerian hedgehog, is a mammal species in the family Erinaceidae native to Algeria, Libya, Malta, Morocco, Spain, and Tunisia. Little is known about this hedgehog, even though the most common breed of domesticated hedgehogs is a result of crossing a four-toed hedgehog with a North African hedgehog. Because this species of hedgehog is native to Africa, it has been suggested that it was introduced by humans to the other countries where it is now found, including Spain and the Canary Islands. Of the four African hedgehog species, the North African hedgehog is the only one of these hedgehogs that occurs outside Africa. Because the North African hedgehog has such a wide habitat range and has a seemingly stable population, both in the wild and in the domesticated capacity, it does not appear to currently be at risk.
The Southern African hedgehog is a species of mammal in the family Erinaceidae. It is found in Angola, Botswana, Lesotho, Namibia, South Africa, Tanzania and Zimbabwe.
The desert hedgehog is a species of mammal in the family Erinaceidae.
The European hedgehog was brought to New Zealand by British colonists in the 1870s as a way to deal with insect pests that had hitched a ride on crops the colonists had brought from their homeland for farming. Long regarded as a gardener’s helper in Britain, the introduction of Hedgehogs seemed a good solution to the lack of natural predators for these pests in New Zealand. They have since spread throughout the country, being absent only in inhospitable environments. The general public has a benign attitude to them in urban environments, but conservationists and regional councils regard them as pests, as they prey on native animals and compete with them for food.
Badger predation of hedgehogs was high in the study site and the main cause of death