Erinaceidae

(vertebrate zoology) The hedgehogs, a family of mammals in the order Insectivora characterized by dorsal and lateral body spines.

(Erinaceidae)

Class: Mammalia

Order: Insectivora

Family: Erinaceidae

Thumbnail description
Small, short-legged animals, five toes on each foot, gait plantigrade; muzzle generally pointed, moderately to greatly elongate, eyes small; pelage may be spiny (hedgehogs) or soft (gymnures)

Size
Head and body length: 4–12 in (10–30 cm); tail:0.4–12 in (1–30 cm); weight: 0.5–38 oz (15–1,100 g)

Number of genera, species
8 genera; 21 species

Habitat
Varies from woodland to grassland, deserts and urban parks for hedgehogs; gymnures restricted to humid forests and meadows

Conservation status
Critically Endangered: 1 species; Endangered: 3 species; Vulnerable: 2 species; Lower Risk/Near Threatened: 1 species

Distribution
Europe, Asia, and Africa

Evolution and systematics

Erinaceidae is a small family, containing just 21 species. The fossil record is rather sparse, with a further 21 extinct species described so far. The family appears to have its origins in North America in the mid Palaeocene, about 60 million years ago (mya). American erinaceids went extinct about 5 mya, but not before further lineages had been established in Europe, Asia, and Africa (about 58, 55, and 23 mya respectively).

Modern erinaceids are split into two quite distinct subgroups, the spiny hedgehogs (subfamily Erinaceinae) and the soft-furred gymnures (known most correctly as subfamily Hylomyinae, but also often referred to as Echinosorinae or Galericinae). Within the hedgehogs there are 14 species in five well-described genera. The taxonomy of the gymnures is rather less clear-cut. There are seven species, including the long-eared lesser gymnure (Hylomys megalotis), which was described in 2002. Prior to 1991, there were five recognized genera, but Neohylomys and Neotetracus have since been reclassified as subgenera of Hylomys. As of 2002, Hylomys is the largest genus in the family with five species, but these are highly variable and the expectation is that further revisions will come.

Physical characteristics

The characteristics that describe members of the family Erinaceidae are generally considered primitive. They are typical insectivores—small animals, with short legs and large feet. Feet have five digits, except in some of the African hedgehogs (genus Atelerix) in which the hallux or big toe is reduced or vestigial. All erinaceids walk with a flat-footed "plantigrade" gait. The two bones of the lower hind leg, the tibia and fibula, are fused into one. The tail is hairy and variable in length, the muzzle is elongated—more so in the gymnures than the hedgehogs. The eyes are small, though better developed than those of most other insectivores. The skulls of hedgehogs and gymnures vary quite considerably, from long and narrow to short and broad. All have a small braincase.

As a general rule, hedgehogs are more derived than gymnures, which have retained many characteristics of their early insectivore ancestors. The most obvious difference between the two subfamilies is the coat. While the gymnures and moonrats are covered in pelage of soft fur, the hedgehogs sport a dense coat of narrow spines, starting on the head and covering the back and flanks. The color varies between and within species, but is usually some shade of yellow- or grayish brown to black.

Hedgehogs and gymnures have similar dentition. The dental formula for the family is (I2–3/3 C1/1 P3–4/2–4 M3/3) × 2 = 63–44. The first incisors are large. In gymnures, there are three pairs of incisors in each jaw, while hedgehogs have lost the third lower pair. The muzzle or rostrum of hedgehogs is shorter than in the gymnures, which have retained a narrow, shrew-like snout.

Distribution

The Erinaceidae is now an exclusively Old World family, with representatives throughout Europe, Asia, and Africa. There is also a pronounced geographical demarcation between the two subfamilies—the Erinaceinae (hedgehogs) are widespread, but except for the Chinese hedgehog (Erinaceus amurensis), they are not found with the Hylomyinae (gymnures and moonrats). The latter are restricted to Southeast Asia. Hedgehogs fare well in cool temperate to tropical climates between about 66°N (Erinaceus europaeus) and 34°S (Atelerix frontalis). The gymnures are essentially a tropical and subtropical group, but they live in a wide range of altitudes, from sea level to 11,000 ft (3,400 m) (Hylomys suillus).

Habitat

As a group of small, "primitive" animals, the erinaceids, and especially the hedgehogs, exploit a surprising diversity of habitats, from mangrove forest to stony desert, urban parks to alpine meadows. In all cases, the main limiting factors are the availability of suitable daytime shelters and food—especially of invertebrate prey. A hedgehog has a fairly small home range with an approximate 120-yd (110-m) radius from its nest. The nest is built in dry litter under tangles of hedge or bush, rock crevices, termite mounds or underbuildings. The hedgehog chatters, snorts or softly growls if its range is invaded by another animal. The gymnures live predominantly in humid forests, but this is more indicative of the availability of suitable food in such places than of their intolerance of dry habitats.

Behavior

For the most part, erinaceids are nocturnal; although the Malayan moonrat (Echinosorex gymnura) and lesser gymnure (Hylomys suillus) may also forage by day. Species living in temperate zones may be forced to begin foraging before sunset in mid-summer. As a general rule, erinaceids are terrestrial, living and feeding at ground level. Most are competent climbers and swim well—E. gymnura may even be least partially aquatic. Digging ability varies, but some species, such as the Indian and the long-eared hedgehogs (Paraechinus micropus and Hemiechinus auritus) are very good burrowers.

Most members of the Erinaceidae are able to enter torpor and thus tolerate bad weather and seasonal food shortages by hibernating in winter or estivating during droughts. Hibernation of the European hedgehog, (Erinaceus europaeus), in colder parts of its range may last six or seven months, during which the heart rate drops from about 188 beats per minute to around 22, and body temperature may fall to just 1°C (34°F). Prolonged hibernation puts enormous strain on the animals reserves of stored fat and those that do not put on enough weight in the fall will not survive.

All the well-studied species are essentially solitary and territorial as adults. Small groups of three or four have been reported for some species, but these probably represent females with subadult young of the year. Fights are seemingly rare, but individuals may react aggressively to threats, giving rapid hissing snorts. Interestingly, an almost identical sound is produced by female hedgehogs during courtship, presumably in response to close approach of another individual, the male.

All erinaceids use scent to mark their home range, but olfactory cues appear to be particularly important for the gymnures, several of which have a strong musky odor that is obvious even to the human nose. Among the other senses, hearing is apparently most sensitive, while eyesight is not particularly acute. One of the most distinctive and unusual aspects of erinaceid behavior is "self-anointing," an activity performed by all species of hedgehog. Apparently triggered by olfactory cues such as strong-smelling or noxious plants or chemicals, this behavior starts with the animals licking or chewing the source of the smell, and producing copious amounts of frothy saliva. The saliva (and presumably with it the chemical trigger, whatever it may be) is then spread over the spines with quick flicks of the tongue and distinctive jerking movements of the head. Presumably the spines provide a surface area from which scent can be dispersed, but so far there is no really satisfactory explanation for the function of self-anointing. Theories range from attracting mates to deterring predators or repelling parasites, but none stand up to rigorous investigation or satisfactorily account for the diversity of trigger substances or the wide range of situations in which animals will suddenly devote all their attention to this odd behavior.

Gymnures are relatively secretive animals, while hedgehogs, with the benefit of their spiny defenses, are more bold. When a hedgehog is threatened, it curls itself into a tight ball by means of well-developed abdominal muscles that act like the cord on a drawstring bag. The head, feet and tail are all tucked away and the spines are erected, presenting a potential predator with nothing but a puzzling spiky ball. Some predators, including badgers and foxes, learn the art of unrolling hedgehogs and may become specialist hedgehog eaters.

Feeding ecology and diet

All hedgehogs and gymnures feed primarily on insects and other invertebrates including worms, spiders, and terrestrial mollusks. Being larger than most other members of the order Insectivora, some are also able to take some larger prey, including reptiles, amphibians, and in some cases small mammals. Hedgehogs are also rather notoriously fond of birds' eggs—the introduction of the European hedgehog to islands including New Zealand has proved disastrous for populations of ground nesting birds. Most species will also consume non-animal matter such as fruit, seeds, and fungi.

Several species of hedgehog sometimes eat venomous animals such as vipers, scorpions, and bees, as well as toxic beetles and spiders, with no apparent ill effects. Their resistance to adder venom can be up to 40 times that of laboratory mice, and they can consume the beetle toxin cantharidin in quantities equivalent to 3,000 times the dose toxic to humans.

Feeding takes place predominantly at night, when the animals may travel some distance along regular pathways, shoving their noses into nooks and crannies and rummaging about in the leaf litter, or sometimes digging into the top layer of soil. Most food is eaten as and when the animal finds it but the Indian hedgehog (Paraechinus micropus) is known to hide excess food in its burrow as an insurance policy against future shortages.

Reproductive biology

Female erinaceids have between two and five pairs of mammae (a maximum of four pairs in the gymnures). Thus the theoretical maximum litter size is 10, but in reality they average between two and five young per litter. Gestation periods range between 30 and 40 days and the young are born blind, helpless, and virtually naked. In the hedgehogs, the first spines may erupt before birth but they are very soft and unpigmented. Adult-type spines usually begin to grow within the first week of life, and the curling response develops within a few weeks. Care of the young is always the sole responsibility of the mother—males play no part beyond courtship and mating, which is polygynous. The suckling period in hedgehogs is between five and seven weeks, and longevity is up to seven years.

Conservation status

Of the 22 species in the family Erinaceidae recognized here, three are officially threatened. Hugh's hedgehog (Mesechinus hughi) is listed as Vulnerable by the IUCN, the Hainan gymnure (Hylomys hainanensis) and both species of Philippine gymnure (Podogymnura truei and P. aureospinula) are Endangered. The IUCN regards Hylomys suillus parvus as a full species and lists it as Critically Endangered, as well as listing Hemiechinus nudiventris as Vulnerable and Hylomys sinensis as Lower Risk/Near Threatened. The chief threats to these species are habitat fragmentation and modification, for example, logging and agricultural development. The southern African hedgehog (Atelerix frontalis) is considered Rare and is listed on Appendix 2 of the CITES in order to prevent uncontrolled collection for the pet trade.

Significance to humans

Erinaceids have little economic importance. As a group, the gymnures are not well known and have little use to humans save occasional use in laboratory experiments. Hedgehogs, on the other hand, have been used to a limited extent by humans throughout history. The meat of hedgehogs is good, but while most species are sometimes eaten as bushmeat or feature in traditional country dishes they are not bred in captivity for this (or any other) purpose. There is a strong association between hedgehogs and European gypsies, who not only eat the animal's meat, but also regard it as an ally against malign mochadi entities such as cats and non-gypsy people.

Hedgehog body parts have been used by many cultures in traditional healing, magic and witch doctoring. The meat has been purported to have cleansing properties and various body parts have apparently been used in the treatment of ailments including leprosy, boils, colic and baldness.

Hedgehogs also appear widely in folklore. They are mentioned in the writings of Pliny and Shakespeare and famous hedgehogs include Mrs. Tiggywinkle, the bustling, petticoated washerwoman in the story by Beatrix Potter and Sonic the Hedgehog—the manic blue-spined hero of the computer game by Sega.

Hedgehogs are among the few wild mammals that have adapted to life alongside people in towns. They are kept as pets and are welcome visitors to gardens, where they help out by eating invertebrate pests. Many people put out food specially for hedgehogs and enjoy watching their spiny visitors dining on bread and milk or canned dog food from a saucer on the back lawn.

Species accounts

Resources

McDonald, D. Collins Field Guide: Mammals of Britain and Europe. London: Harper Collins, 1993.

Nowak, R. "Hedgehogs and Gymnures (Insectivora; Family Erinaceidae)." In Walker's Mammals of the World, 6th ed. Vol. 1, Baltimore and London: Johns Hopkins University Press, 1999.

Reeve, N. Hedgehogs. London: Poyser Natural History, 1994.

Corbet, G. B. "The Family Erinaceidae: A Synthesis of its Taxonomy, Phylogeny, Ecology and Zoogeography." Mammal Review 18 (1988): 117–172.

Jenkins, P. D., and M. F. Robinson. "Another Variation on the Gymnure Theme: Description of a New Species of Hylomys (Lipotyphla, Erinacaidae, Galericinae)." Bulletin of the Natural History Museum, Zoology Series 68 (2002): 1–11.

IUCN Species Survival Commission, Insectivore Specialist Group, Dr. Werner Haberl, Chair. Hamburgerstrasse 11, Vienna, A-1050 Austria. E-mail: shrewbib@sorex.vienna.at Web site:

Hedgehog Valley. March 31, 2003. .

The International Hedgehog Association. The International Hedgehog Club. January 1, 2003. .

Stone, David R. "Family Erinaceidae: The Hedgehogs, Moonrats and Gymnures." In Eurasian Insectivores and Tree Shrews: Status Survey and Conservation Action Plan. 1995. ITSES Specialist Group, IUCN..

[Article by: Amy-Jane Beer, PhD]

The noun has one meaning:

Meaning #1: true hedgehogs
  Synonym: family Erinaceidae

Erinaceomorpha[1] Fossil range: Eocene–Recent PreЄ Є O S D C P T J K Pg N
Erinaceus europaeus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Eutheria
Superorder:	Laurasiatheria
Order:	Erinaceomorpha Gregory, 1910
Family:	Erinaceidae G. Fischer, 1814
Subfamilies & Genera
Erinaceinae Atelerix Erinaceus Hemiechinus Mesechinus Paraechinus Galericinae Echinosorex Hylomys Neohylomys Neotetracus Podogymnura

Erinaceidae is the only living family in the order of the Erinaceomorpha. It contains the well-known hedgehogs (subfamily Erinaceinae) of Eurasia and Africa and the gymnures or moonrats (subfamily Galericinae) of South-east Asia. This family was once considered part of the order Insectivora, but that polyphyletic order is now considered defunct.^[1]

Contents 1 Characteristics 2 Evolution 3 Classification 4 References

Characteristics

Erinaceids are generally shrew-like in form, with long snouts and short tails. They are, however, much larger than shrews, ranging from 10-15 cm in body length and 40-60 grams in weight, in the case of the Short-tailed Gymnure, up to 26-45 cm and 1-1.4 kilograms in the Greater Moonrat. All but one species have five toes in each foot, in some cases with strong claws for digging, and they have large eyes and ears. Hedgehogs possess hair modified into sharp spines to form a protective covering over the upper body and flanks, while gymnures have only normal hair. All species have anal scent glands, but these are far better developed in gymnures, which can have a powerful odor^[2].

Erinaceids are omnivorous, with the major part of their diet consisting of insects, earthworms, and other small invertebrates. They also eat seeds and fruit, and occasionally bird's eggs, along with any carrion they come across. Their teeth are sharp and suited for impaling invertebrate prey. The dental formula for erinaceids is:

Hedgehogs are nocturnal, but gymnures are less so, and may be active during the day. Many species live in simple burrows, while others construct temporary nests on the surface from leaves and grass, or shelter in hollow logs or similar hiding places. Erinaceids are solitary animals outside the breeding season, and the father plays no role in raising the young^[2].

Female erinaceids give birth after a gestation period of around six to seven weeks. The young are born blind and hairless, although hedgehogs begin to sprout their spines within 36 hours of birth.

Evolution

Erinaceids are a relatively primitive group of placental mammals, having changed little since their origin in the Eocene. The so-called 'giant hedgehog' (actually a gymnure) Deinogalerix, from the Miocene of Italy, was the size of a large rabbit, and may have eaten vertebrate prey or carrion, rather than insects^[3].

Classification

There are 10 genera and 24 species of erinaceid.

• ORDER ERINACEOMORPHA
  • †Family Amphilemuridae
    • †Genus Alsaticopithecus
    • †Genus Amphilemur
    • †Genus Gesneropithex
    • †Genus Macrocranion
    • †Genus Pholidocercus
  • Family Erinaceidae
    • Subfamily Erinaceinae (Hedgehogs)
      • Genus Atelerix
        • Four-toed Hedgehog, Atelerix albiventris
        • North African Hedgehog, Atelerix algirus
        • Southern African Hedgehog, Atelerix frontalis
        • Somali Hedgehog, Atelerix sclateri
      • Genus Erinaceus
        • Amur Hedgehog, Erinaceus amurensis
        • Southern White-breasted Hedgehog, Erinaceus concolor
        • European Hedgehog, Erinaceus europaeus
        • Northern White-breasted Hedgehog, Erinaceus roumanicus
      • Genus Hemiechinus
        • Long-eared Hedgehog, Hemiechinus auritus
        • Indian Long-eared Hedgehog, Hemiechinus collaris
      • Genus Mesechinus
        • Daurian Hedgehog, Mesechinus dauuricus
        • Hugh's Hedgehog, Mesechinus hughi
      • Genus Paraechinus
        • Desert Hedgehog, Paraechinus aethiopicus
        • Brandt's Hedgehog, Paraechinus hypomelas
        • Indian Hedgehog, Paraechinus micropus
        • Bare-bellied Hedgehog, Paraechinus nudiventris
    • Subfamily Galericinae (Gymnures, or Moonrats)
      • Genus Deinogalerix(Extinct)
      • Genus Echinosorex
        • Greater Moonrat, Echinosorex gymnura
      • Genus Hylomys
        • Long-eared Gymnure, Hylomys megalotis
        • Dwarf Gymnure, Hylomys parvus
        • Short-tailed Gymnure or Lesser Moonrat, Hylomys suillus
      • Genus Neohylomys
        • Hainan Gymnure, Neonylomys hainanensis
      • Genus Neotetracus
        • Shrew Gymnure, Neotetracus sinensis
      • Genus Podogymnura
        • Dinagat Gymnure, Podogymnura aureospinula
        • Mindanao Gymnure, Podogymnura truei

References

1. ^ ^{a b} Hutterer, Rainer (November 16, 2005). Don E. Wilson and DeeAnn M. Reeder. ed. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 212-219. ISBN 978-0-8018-8221-0. http://www.bucknell.edu/msw3. 
2. ^ ^{a b} Wroot, Andrew (1984). Macdonald, D.. ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 750–757. ISBN 0-87196-871-1. 
3. ^ Savage, RJG, & Long, MR (1986). Mammal Evolution: an illustrated guide. New York: Facts on File. pp. 48–49. ISBN 0-8160-1194-X. 

v • d • e Extant mammal orders by infraclass Kingdom Animalia · Phylum Chordata · Subphylum Vertebrata · (unranked) Amniota Australosphenida Monotremata (Platypus and echidnas) Metatheria (Marsupial inclusive) Didelphimorphia (Opossums) · Paucituberculata (Shrew opossums) · Microbiotheria (Monito del Monte) · Notoryctemorphia (Marsupial moles) · Dasyuromorphia (Quolls and dunnarts) · Peramelemorphia (Bilbies and bandicoots) · Diprotodontia (Kangaroos and relatives) Eutheria Afrosoricida (Tenrecs and golden moles) · Macroscelidea (Elephant shrews) · Tubulidentata (Aardvark) · Hyracoidea (Hyraxes) · Proboscidea (Elephants) · Sirenia (Dugongs and manatees) · Cingulata (Armadillos) · Pilosa (Anteaters and sloths) · Scandentia (Treeshrews) · Dermoptera (Colugos) · Primates · Rodentia (Rodents) · Lagomorpha (Rabbits and relatives) · Erinaceomorpha (Hedgehogs and relatives) · Soricomorpha (Shrews and moles) · Chiroptera (Bats) · Pholidota (Pangolins) · Carnivora · Perissodactyla (Odd-toed ungulates) · Artiodactyla (Even-toed ungulates) · Cetacea (Whales and dolphins)

v • d • e Extant Erinaceomorpha species by subfamily Kingdom Animalia · Phylum Chordata · Class Mammalia · Infraclass Eutheria · Superorder Laurasiatheria Erinaceinae (Hedgehogs) Atelerix Four-toed Hedgehog (A. albiventris) · North African Hedgehog (A. algirus) · Southern African Hedgehog (A. frontalis) · Somali Hedgehog (A. sclateri) Erinaceus Amur Hedgehog (E. amurensis) · Southern White-breasted Hedgehog (E. concolor) · West European Hedgehog (E. europaeus) · Northern White-breasted Hedgehog (E. roumanicus) Hemiechinus Long-eared Hedgehog (H. auritus) · Indian Long-eared Hedgehog (H. collaris) Mesechinus Daurian Hedgehog (M. dauuricus) · Hugh's Hedgehog (M. hughi) Paraechinus Desert Hedgehog (P. aethiopicus) · Brandt's Hedgehog (P. hypomelas) · Indian Hedgehog (P. micropus) · Bare-bellied Hedgehog (P. nudiventris) Galericinae (Gymnures) Echinosorex Moonrat (E. gymnura) Hylomys Long-eared Gymnure (H. megalotis) · Dwarf Gymnure (H. parvus) · Short-tailed Gymnure (H. suillus) Neohylomys Hainan Gymnure (N. hainanensis) Neotetracus Shrew Gymnure (N. sinensis) Podogymnura Dinagat Gymnure (P. aureospinula) · Mindanao Gymnure (P. truei) Category

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