Echidna
Echidnas Temporal range:
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Short-beaked echidna | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Monotremata |
Family: | Tachyglossidae Gill , 1872
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Type genus | |
Tachyglossus
, 1811 | |
Species | |
Genus | |
Echidna range
Sir David's long-beaked echidna |
Echidnas (
Echidnas evolved between 20 and 50 million years ago, descending from a platypus-like monotreme.[4] This ancestor was aquatic, but echidnas adapted to life on land.[4]
Etymology
Echidnas are possibly named after Echidna, a creature from Greek mythology who was half-woman, half-snake, as the animal was perceived to have qualities of both mammals and reptiles.[citation needed] An alternative explanation is a confusion with Ancient Greek: ἐχῖνος, romanized: ekhînos, lit. 'hedgehog, sea urchin'.[5]
Physical characteristics
Echidnas are medium-sized, solitary mammals covered with coarse hair and spines.[6] The spines are modified hairs and are made of keratin, the same fibrous protein that makes up fur, claws, nails, and horn sheaths in animals.[2]
Superficially, they resemble the anteaters of South America and other spiny mammals such as hedgehogs and porcupines. They are usually black or brown in coloration. There have been several reports of albino echidnas with pink eyes and white spines.[6] They have elongated and slender snouts that function as both mouth and nose, and which have electrosensors to find earthworms, termites, ants, and other burrowing prey.[7] This is similar to the platypus, which has 40,000 electroreceptors on its bill, but the long-beaked echidna has only 2,000, while the short-beaked echidna, which lives in a drier environment, has no more than 400 at the tip of its snout.[8]
Echidnas have short, strong limbs with large claws, and are powerful diggers. Their hind claws are elongated and curved backwards to aid in digging. Echidnas have tiny mouths and toothless jaws, and feed by tearing open soft logs,
Despite their appearance, echidnas are capable swimmers, as they evolved from
The first European drawing of an echidna was made in Adventure Bay, Tasmania by HMS Providence's third lieutenant George Tobin during William Bligh's second breadfruit voyage.[10]
Diet
The
Like all mammals, echidnas feed their young on milk, which contains various factors to sustain their growth and development.[13][14]
Habitat
Echidnas do not tolerate extreme temperatures; they shelter from harsh weather in caves and rock crevices. Echidnas are found in forests and woodlands, hiding under vegetation, roots or piles of debris. They sometimes use the burrows (both abandoned and in use) of animals such as rabbits and wombats. Individual echidnas have large, mutually overlapping territories.[12]
Anatomy
Echidnas and platypuses are the only egg-laying mammals, the
Male echidnas have non-venomous spurs on the hind feet, similar to the venomous male platypus.[15]
Due to their low metabolism and accompanying stress resistance, echidnas are long-lived for their size; the longest recorded lifespan for a captive echidna is 50 years, with anecdotal accounts of wild individuals reaching 45 years.[16]
The echidna's brain is half
Reproduction
The female lays a single soft-shelled, leathery egg 22 days after mating, and deposits it directly into her pouch. An egg weighs 1.5 to 2 grams (0.05 to 0.07 oz) Male echidnas have a four-headed penis.[26] 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. Each time it copulates, it alternates heads in sets of two.[27][28] When not in use, the penis is retracted inside a preputial sac in the cloaca. The male echidna's penis is 7 centimetres (2.8 in) long when erect, and its shaft is covered with penile spines.[29] These may be used to induce ovulation in the female.[30]
It is a challenge to study the echidna in its natural habitat, and they show no interest in mating while in captivity. Prior to 2007, no one had ever seen an echidna ejaculate. There have been previous attempts, trying to force the echidna to ejaculate through the use of electrically stimulated ejaculation in order to obtain semen samples but this has only resulted in the penis swelling.[28]
Breeding season begins in late June and extends through September. During mating season, a female may be followed by a line or "train" of up to 10 males, the youngest trailing last, and some males switching between lines.[12]
Threats
Echidnas are very timid. When frightened, they attempt to partially bury themselves and curl into a ball similar to a hedgehog. Strong front arms allow echidnas to dig in and hold fast against a predator pulling them from the hole.
Their many predators include
They are easily stressed and injured by handling. Some ways to help echidnas include picking up litter, causing less pollution, planting vegetation for shelter, supervising pets, reporting hurt echidnas, and leaving them undisturbed.[12]
Evolution
The divergence between oviparous (egg-laying) and viviparous (offspring develop internally) mammals is believed to date to the Triassic period.[31] Most findings from genetics studies (especially of nuclear genes) are in agreement with the paleontological dating, but some other evidence, like mitochondrial DNA, give slightly different dates.[32]
Molecular clock data suggest echidnas split from platypuses between 19 and 48 million years ago, so that platypus-like fossils dating back to over 112.5 million years ago represent basal forms, rather than close relatives of the modern platypus.[4] This would imply that echidnas evolved from water-foraging ancestors that returned to land living, which put them in competition with marsupials.[further explanation needed] Although extant monotremes lack adult teeth (platypuses have teeth only as juveniles), many extinct monotreme species have been identified based on the morphology of their teeth.[7] Of the eight genes involved in tooth development, four have been lost in both platypus and echidna, indicating that the loss of teeth occurred before the echidna-platypus split.[22]
Further evidence of
It has been suggested that echidnas originally evolved in New Guinea when it was isolated from Australia and from marsupials. This would explain their rarity in the fossil record, their abundance in present times in New Guinea, and their original adaptation to terrestrial niches, presumably without competition from marsupials.[33]
Taxonomy
Cladogram of Tachyglossidae by Upham et al. 2019[34][35] | ||||||||||||||||||||||||
|
Echidnas are a small
Zaglossus
The three living Zaglossus species are
. The species are- Western long-beaked echidna (Z. bruijni), of the highland forests;
- Sir David's long-beaked echidna (Z. attenboroughi), discovered by Western science in 1961 (described in 1998) and preferring a still higher habitat;[37]
- Eastern long-beaked echidna (Z. bartoni), of which four distinct subspecies have been identified.
The one fossil species is:
- †Zaglossus robustus.
Tachyglossus
The short-beaked echidna (Tachyglossus aculeatus) is found in southern, southeast and northeast New Guinea, and also occurs in almost all Australian environments, from the snow-clad Australian Alps to the deep deserts of the Outback, essentially anywhere ants and termites are available. It is smaller than the Zaglossus species, and it has longer hair.
Despite the similar dietary habits and methods of consumption to those of an anteater, there is no evidence supporting the idea that echidna-like monotremes have been myrmecophagic (ant or termite-eating) since the
Additionally, extinct echidnas continue to be
Megalibgwilia
The genus Megalibgwilia is known only from fossils:
- M. owenii from Late Pleistocene sites in Australia;
- M. robusta from Miocene sites in Australia.
Murrayglossus
The genus Murrayglossus is known only from fossils:[39]
- M. hacketti (previously classified in the genus Zaglossus) from Pleistocene of Western Australia.
As food
The
In popular culture
- The echidna appears on the reverse of the Australian five-cent coin.[43]
- An echidna named Millie was one of the three official mascots for the 2000 Summer Olympics in Sydney.[44]
See also
Notes
- ^ Reverend Peterson Nganjmirra, personal comment.
References
- ^ "Short-Beaked Echidna, Tachyglossus aculeatus". Park & Wildlife Service Tasmania. Archived from the original on 31 March 2016. Retrieved 21 October 2012.
- ^ a b "Spines and Quills". Animal Diversity Web. University of Michigan. Retrieved 13 September 2021.
- ^ Stewart, Doug (April–May 2003). "The Enigma of the Echidna". National Wildlife. Archived from the original on 29 April 2012.
- ^ PMID 19805098.
- ^ "echidna". Online Etymology Dictionary. Retrieved 23 November 2014.
- ^ ISBN 978-0-643-09204-4.
- ^ ISBN 978-0-387-23192-1.
- ^ "Electroreception in fish, amphibians and monotremes". Map of Life. 7 July 2010.
- ^ "Short-beaked Echidna". Department of Primary Industries, Parks, Water, and Environment. Retrieved 13 April 2013.
- ^ "George Tobin journal and sketches on HMS Providence, 1791-1793, with additional material to 1831". State Library - New South Wales. Retrieved 4 December 2020.
- ^ a b "Zaglossus bruijni". AnimalInfo.org.
- ^ a b c d e f g Carritt, Rachel. "Echidnas: Helping them in the wild" (PDF). NSW National Parks and Wildlife Service. Retrieved 13 April 2013.
- ^ Stannard, Hayley J.; Old, Julie M. (2023). "Wallaby joeys and platypus puggles are tiny and undeveloped when born. But their mother's milk is near-magical". The Conversation.
- PMID 32612884.
- ISBN 0123038502.
- ^ Cason, M. (2009). "Tachyglossus aculeatus". Animal Diversity. Retrieved 21 October 2012.
- ^ Gill, Victoria (19 November 2012). "Are these animals too 'ugly' to be saved?". BBC News.
- S2CID 145583615.
- ^ Dunbar, R.I.M. "The Social Brain Hypothesis" (PDF). University of Colorado at Boulder, Department of Psychology and Neuroscience. Archived from the original (PDF) on 12 April 2016. Retrieved 4 January 2014.
- S2CID 40439226.
- ^ "Echidnas". wildcare.org.au. Wildcare Australia. Retrieved 20 November 2016.
- ^ a b O'Neil, Dennis. "Echidna Reproduction" Archived 30 April 2015 at the Wayback Machine 12 February 2011. Retrieved on 17 June 2015.
- S2CID 15026875.
Developmental stages of echidna: (A) Echidna eggs; (B) Echidna puggle hatching from egg...
- ^ Calderwood, Kathleen (18 November 2016). "Taronga Zoo welcomes elusive puggles". ABC News. Sydney. Retrieved 20 November 2016.
- ^ "Short-beaked echidna (Tachyglossus aculeatus)". Arkive.org. Archived from the original on 13 August 2009. Retrieved 21 October 2009.
- ^ Grützner, F., B. Nixon, and R. C. Jones. "Reproductive biology in egg-laying mammals." Sexual Development 2.3 (2008): 115-127.
- S2CID 40632746.
- ^ a b Shultz, N. (26 October 2007). "Exhibitionist spiny anteater reveals bizarre penis". New Scientist. Retrieved 12 April 2020.
- ISBN 978-0-643-09928-9. Retrieved 15 March 2013.
- ISBN 0-8014-1753-8.
- PMID 18216270.
- PMID 14667856.
- S2CID 247542433.
- PMID 31800571.
- .
- ^ S2CID 84750399.
- ^ "First-ever images prove 'lost echidna' not extinct". BBC News. 10 November 2023. Retrieved 12 November 2023.
- PMC 2824408.
- S2CID 247542433.
- ^ Garde, Murray. "ngarrbek". Bininj Kunwok Online Dictionary. Bininj Kunwok Regional Language Centre. Retrieved 29 July 2020.
- ISBN 1862543062.
- ^ Garde, Murray. "mandak". Bininj Kunwok Online Dictionary. Bininj Kunwok Regional Language Centre. Retrieved 29 July 2020.
- ^ "Royal Australian Mint: 5 cents". 8 January 2016. Retrieved 3 May 2020.
- ^ Sydney 2000: The Mascot – Olympics.com. Retrieved June 4, 2022.
Bibliography
- Ronald M. Nowak (1999), Walker's Mammals of the World (6th ed.), Baltimore: Johns Hopkins University Press, LCCN 98023686
External links
- Stewart, Doug (April 2003). "The Enigma of the Echidna". National Wildlife. Retrieved 3 February 2017.
- Parker, J. (1 June 2000). "Echidna Love Trains". ABC Science. Australian Broadcasting Corporation.
- Rismiller, Peggy (2005). "Echidna research, Kangaroo island". Pelican Lagoon Research & Wildlife Centre. Archived from the original on 21 February 2015. Retrieved 15 July 2012.
- "Tachyglossidae". NCBI Taxonomy Browser. 9259.