Echidna
Encyclopedia
Echidnas also known as spiny anteaters, belong to the family
Tachyglossidae in the monotreme
order of egg
-laying mammal
s. There are four extant species, which, together with the platypus
, are the only surviving members of that order
and are the only extant mammals that lay eggs. Although their diet consists largely of ants and termites, they are no more closely related to the true anteaters
of the Americas
than to any other placental mammal. They live in New Guinea
and Australia
. The echidnas are named after a monster in ancient Greek mythology
.
and spine
s. Superficially, they resemble the anteaters of South America and other spiny mammals such as hedgehog
s and porcupine
s. They have snouts which have the functions of both mouth and nose. Their snouts are elongated and slender. Like the platypus, they are equipped with electrosensors, but while the platypus has 40,000 electroreceptors on its bill, the long-billed echidna has only 2,000, and the short-billed echidna, which lives in a drier environment, has no more than 400 located at the tip of its snout. They have very short, strong limb
s with large claw
s, and are powerful diggers. Echidnas have a tiny mouth
and a toothless jaw
. The echidna feeds by tearing open soft logs, anthills and the like, and using its long, sticky tongue
, which protrudes from its snout, to collect prey. The short-beaked echidna
's diet consists largely of ants and termites, while the Zaglossus species typically eats worms and insect larvae.
The long-beaked echidnas have sharp, tiny spines on their tongues that help capture their prey.
Echidnas and the platypus are the only egg-laying mammals, known as monotremes. The female lays a single soft-shelled, leathery egg
22 days after mating, and deposits it directly into her pouch. Hatching takes place after ten days; the young echidna, called a puggle, then sucks milk
from the pore
s of the two milk patches
(monotremes have no nipple
s) and remains in the pouch for 45 to 55 days, at which time it starts to develop spines. The mother digs a nursery burrow and deposits the puggle, returning every five days to suckle it until it is weaned at seven months. The average wild echidna can grow as old as 16 years.
Male echidnas have a four-headed penis
. During mating, the heads on one side "shut down" and do not grow in size; the other two are used to release semen into the female's two-branched reproductive tract. The heads used are swapped each time the mammal copulates.
Contrary to previous research, the echidna does enter REM sleep, albeit only when the ambient temperature is around 25°C (77°F). At temperatures of 15°C (59°F) and 28°C (~82°F), REM sleep is suppressed.
and fossil dating suggest echidnas split from platypus
es 19–48 million years ago. Echidnas evolved from water-foraging ancestors which returned to living completely on the land, even though this put them in competition with marsupials. Because of this, it has been suggested that "oviparous reproduction in monotremes confers advantages over marsupials, a view consistent with present ecological partitioning between monotremes
and marsupials."
into three genera
. The genus Zaglossus includes three extant species
and two species known only from fossil
s, while only one extant species from the genus Tachyglossus is known. The third genus, Megalibgwilia
, is known only from fossils.
to New Guinea
. They are rare and are hunted for food. They forage in leaf litter on the forest floor, eating earthworm
s and insect
s. The species are:
The two fossil species are:
(Tachyglossus aculeatus) is found in southeast New Guinea
, and also occurs in almost all Australia
n environments, from the snow-clad Australian Alps
to the deep desert
s of the Outback
, essentially anywhere ants and termites are available. It is smaller than the Zaglossus species, and it has longer hair.
is known only from fossils:
is a red echidna featured in the video game series Sonic the Hedgehog. Knuckles made his debut in Sonic the Hedgehog 3
for the Sega Mega Drive
.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Tachyglossidae in the monotreme
Monotreme
Monotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals...
order of egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
-laying mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. There are four extant species, which, together with the platypus
Platypus
The platypus is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young...
, are the only surviving members of that order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
and are the only extant mammals that lay eggs. Although their diet consists largely of ants and termites, they are no more closely related to the true anteaters
Anteater
Anteaters, also known as antbear, are the four mammal species of the suborder Vermilingua commonly known for eating ants and termites. Together with the sloths, they compose the order Pilosa...
of the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
than to any other placental mammal. They live in New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. The echidnas are named after a monster in ancient Greek mythology
Echidna (mythology)
In Greek mythology, Echidna was half woman half snake, known as the "Mother of All Monsters" because most of the monsters in Greek myth were mothered by her...
.
Description
Echidnas are small, solitary mammals covered with coarse hairHair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....
and spine
Spine (zoology)
A spine is a hard, thorny or needle-like structure which occurs on various animals. Animals such as porcupines and sea urchins grow spines as a self-defense mechanism. Spines are often formed of keratin...
s. Superficially, they resemble the anteaters of South America and other spiny mammals such as hedgehog
Hedgehog
A hedgehog is any of the spiny mammals of the subfamily Erinaceinae and the order Erinaceomorpha. There are 17 species of hedgehog in five genera, found through parts of Europe, Asia, Africa, and New Zealand . There are no hedgehogs native to Australia, and no living species native to the Americas...
s and porcupine
Porcupine
Porcupines are rodents with a coat of sharp spines, or quills, that defend or camouflage them from predators. They are indigenous to the Americas, southern Asia, and Africa. Porcupines are the third largest of the rodents, behind the capybara and the beaver. Most porcupines are about long, with...
s. They have snouts which have the functions of both mouth and nose. Their snouts are elongated and slender. Like the platypus, they are equipped with electrosensors, but while the platypus has 40,000 electroreceptors on its bill, the long-billed echidna has only 2,000, and the short-billed echidna, which lives in a drier environment, has no more than 400 located at the tip of its snout. They have very short, strong limb
Limb (anatomy)
A limb is a jointed, or prehensile , appendage of the human or other animal body....
s with large claw
Claw
A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...
s, and are powerful diggers. Echidnas have a tiny mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
and a toothless jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
. The echidna feeds by tearing open soft logs, anthills and the like, and using its long, sticky tongue
Tongue
The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...
, which protrudes from its snout, to collect prey. The short-beaked echidna
Short-beaked Echidna
The short-beaked echidna , also known as the spiny anteater because of its diet of ants and termites, is one of four living species of echidna and the only member of the genus Tachyglossus...
's diet consists largely of ants and termites, while the Zaglossus species typically eats worms and insect larvae.
The long-beaked echidnas have sharp, tiny spines on their tongues that help capture their prey.
Echidnas and the platypus are the only egg-laying mammals, known as monotremes. The female lays a single soft-shelled, leathery egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
22 days after mating, and deposits it directly into her pouch. Hatching takes place after ten days; the young echidna, called a puggle, then sucks milk
Milk
Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...
from the pore
Lactiferous duct
Lactiferous ducts lead from the lobules of the mammary gland to the tip of the nipple. They are also referred to as galactophores, galactophorous ducts, mammary ducts, mamillary ducts and milk ducts...
s of the two milk patches
Mammary gland
A mammary gland is an organ in mammals that produces milk to feed young offspring. Mammals get their name from the word "mammary". In ruminants such as cows, goats, and deer, the mammary glands are contained in their udders...
(monotremes have no nipple
Nipple
In its most general form, a nipple is a structure from which a fluid emanates. More specifically, it is the projection on the breasts or udder of a mammal by which breast milk is delivered to a mother's young. In this sense, it is often called a teat, especially when referring to non-humans, and...
s) and remains in the pouch for 45 to 55 days, at which time it starts to develop spines. The mother digs a nursery burrow and deposits the puggle, returning every five days to suckle it until it is weaned at seven months. The average wild echidna can grow as old as 16 years.
Male echidnas have a four-headed penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
. During mating, the heads on one side "shut down" and do not grow in size; the other two are used to release semen into the female's two-branched reproductive tract. The heads used are swapped each time the mammal copulates.
Contrary to previous research, the echidna does enter REM sleep, albeit only when the ambient temperature is around 25°C (77°F). At temperatures of 15°C (59°F) and 28°C (~82°F), REM sleep is suppressed.
Evolution
Molecular clockMolecular clock
The molecular clock is a technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged. It is used to estimate the time of occurrence of events called speciation or radiation...
and fossil dating suggest echidnas split from platypus
Platypus
The platypus is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young...
es 19–48 million years ago. Echidnas evolved from water-foraging ancestors which returned to living completely on the land, even though this put them in competition with marsupials. Because of this, it has been suggested that "oviparous reproduction in monotremes confers advantages over marsupials, a view consistent with present ecological partitioning between monotremes
and marsupials."
Taxonomy
Echidnas are classifiedBiological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
into three genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
. The genus Zaglossus includes three extant species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
and two species known only from fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s, while only one extant species from the genus Tachyglossus is known. The third genus, Megalibgwilia
Megalibgwilia
Megalibgwilia is a genus of echidna known only from Australian fossils that incorporates the oldest known echidna species. It lived during the Pleistocene, becoming extinct about 50,000 years ago....
, is known only from fossils.
Zaglossus
The three living Zaglossus species are endemicEndemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
. They are rare and are hunted for food. They forage in leaf litter on the forest floor, eating earthworm
Earthworm
Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...
s and insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s. The species are:
- Western long-beaked echidnaWestern Long-beaked EchidnaThe western long-beaked echidna is one of the four extant echidnas and one of three species of Zaglossus that occur in New Guinea. As Tachyglossus bruijni, this is the type species of Zaglossus....
(Zaglossus bruijni), of the highland forestForestA forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
s - Sir David's long-beaked echidnaSir David's Long-beaked EchidnaSir David's long-beaked echidna , also known as Attenborough's long-beaked echidna or the Cyclops long-beaked echidna, is one of three species from the genus Zaglossus to occur in New Guinea. It is named in honour of Sir David Attenborough, the eminent naturalist...
(Zaglossus attenboroughi), described in 1961 and preferring a still higher habitat - Eastern long-beaked echidnaEastern Long-beaked EchidnaThe eastern long-beaked echidna , also known as Barton's long-beaked echidna, is one of three species from the genus Zaglossus to occur in New Guinea...
(Zaglossus bartoni), of which four distinct subspecies have been identified
The two fossil species are:
- †Zaglossus robustusZaglossus robustusZaglossus robustus is an extinct species of long-beaked echidna known from the middle Miocene of Gulgong, New South Wales, Australia. It may belong in the genus Megalibgwilia. The supposed fossil platypus Ornithorhynchus maximus was based on a humerus of this species.-Literature cited:*Hall, B.K....
- †Zaglossus hackettiZaglossus hackettiZaglossus hacketti is an extinct species of long-beaked echidna from Western Australia that is dated from the Pleistocene. It is known only from a few bones found in Western Australia. It was the size of a sheep, weighing probably up to 100 kg . This makes it the largest monotreme to have ever...
Tachyglossus
The short-beaked echidnaShort-beaked Echidna
The short-beaked echidna , also known as the spiny anteater because of its diet of ants and termites, is one of four living species of echidna and the only member of the genus Tachyglossus...
(Tachyglossus aculeatus) is found in southeast New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
, and also occurs in almost all Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n environments, from the snow-clad Australian Alps
Australian Alps
The Australian Alps are the highest mountain ranges of mainland Australia. They are located in southeastern Australia and straddle the Australian Capital Territory, south-eastern New South Wales and eastern Victoria...
to the deep desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
s of the Outback
Outback
The Outback is the vast, remote, arid area of Australia, term colloquially can refer to any lands outside the main urban areas. The term "the outback" is generally used to refer to locations that are comparatively more remote than those areas named "the bush".-Overview:The outback is home to a...
, essentially anywhere ants and termites are available. It is smaller than the Zaglossus species, and it has longer hair.
Megalibgwilia
The genus MegalibgwiliaMegalibgwilia
Megalibgwilia is a genus of echidna known only from Australian fossils that incorporates the oldest known echidna species. It lived during the Pleistocene, becoming extinct about 50,000 years ago....
is known only from fossils:
- Megalibgwilia ramsayi from Late PleistoceneLate PleistoceneThe Late Pleistocene is a stage of the Pleistocene Epoch. The beginning of the stage is defined by the base of the Eemian interglacial phase before the final glacial episode of the Pleistocene 126,000 ± 5,000 years ago. The end of the stage is defined exactly at 10,000 Carbon-14 years BP...
sites in Australia - Megalibgwilia robusta from MioceneMioceneThe Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
sites in Australia
Echidna in pop culture
Knuckles the EchidnaKnuckles the Echidna
Knuckles the Echidna is a video game character of the Sonic the Hedgehog game series, including spin-off games and comics. His first appearance was in Sonic the Hedgehog 3, released in 1994 to introduce a new rival for Sonic. He was presented as an antagonist who was tricked by Dr. Eggman into...
is a red echidna featured in the video game series Sonic the Hedgehog. Knuckles made his debut in Sonic the Hedgehog 3
Sonic the Hedgehog 3
Sonic the Hedgehog 3 is a 1994 platform video game in the Sonic the Hedgehog series for the Sega Mega Drive/Genesis. It was developed in the United States by members of Sonic Team working at Sega Technical Institute, and was published by Sega, debuting worldwide in the first half of 1994...
for the Sega Mega Drive
Sega Mega Drive
The Sega Genesis is a fourth-generation video game console developed and produced by Sega. It was originally released in Japan in 1988 as , then in North America in 1989 as Sega Genesis, and in Europe, Australia and other PAL regions in 1990 as Mega Drive. The reason for the two names is that...
.
External links
- "The Enigma of the Echidna" by Doug Stewart, National Wildlife, April/May 2003.
- Scribbly Gum - Australian Broadcasting Corporation online magazine, article "Echidna Love Trains": Echidna spotting, Trains (breeding behaviour), The amazing puggle (young), Species, Dreaming (REM sleep), Managing populations; June 2000