|Bilby (right) and spinifex hopping mouse at Sydney Wildlife World|
|Distribution of greater bilbies|
The greater bilby (Macrotis lagotis), often referred to simply as the bilby since the lesser bilby (Macrotis leucura) became extinct in the 1950s, is an Australian species of nocturnal omnivorous animal in the order Peramelemorphia. Other vernacular names include dalgyte, pinkie, or rabbit-eared bandicoot. Greater bilbies live in arid parts of northwestern and central Australia. Their range and population is in decline.
Once widespread in arid, semi-arid and relatively fertile areas covering 70 per cent of mainland Australia, by 1995 the bilby was restricted to arid regions and classed as a threatened species. Before the extreme contraction of its range to remote northern desert areas, the species was well known around Adelaide, especially in the city parklands, and it was also recorded as living around Perth.
Greater bilbies have the characteristics of long bandicoot muzzle and very long ears. They are about 29–55 centimetres (11–22 in) in length. Compared to bandicoots, they have a longer tail, bigger ears, and softer, silky fur. The size of their ears allows them to have better hearing as well. At 1 to 2.4 kilograms (2.2 to 5.3 lb), the male is about the same size as a rabbit; although male animals in good condition have been known to grow up to 3.7 kilograms (8.2 lb) in captivity. The female is smaller, and weighs around 0.8 to 1.1 kilograms (1.8 to 2.4 lb). Bilbies have an excellent sense of smell and sharp hearing. Their fur is blue-grey with patches of tan and is very soft. The tail is black and white with a distinct crest.
Unlike bandicoots, they are excellent burrowers and can build extensive tunnel systems with their strong forelimbs and well-developed claws. A bilby typically makes several burrows within its home range, up to about a dozen; and moves between them, using them for shelter both from predators and the heat of the day. The female bilby's pouch faces backward, which prevents her pouch from getting filled with dirt while she is digging.
Greater bilbies are nocturnal omnivores that do not need to drink water, as they get all the moisture they need from their food, which includes insects and their larvae, seeds, spiders, termites, bulbs, fruit, fungi, and very small animals. Most food is found by digging or scratching in the soil, and using their very long tongues.
In captivity, bilbies typically live for at least six years with some specimens reaching ten years of age. However, wild caught bilbies tend to be less than 12 months old. Females become reproductively active at six months of age and can breed all year round if conditions are favourable.
Greater bilbies have a very short gestation period of about 12–14 days, one of the shortest among mammals. The young are only 0.25 in (0.6 cm) long and very underdeveloped when they are born. They must crawl to the mother’s pouch and latch onto one of her eight teats. They leave the pouch after 70–75 days and remain in the natal burrow for two to three weeks before becoming independent. Litters usually consist of one to three joeys and females can have up to four litters per year in favourable conditions.
Greater bilbies are generally solitary marsupials; however, there are some cases in which they travel in pairs. These pairs usually consist of two females, and these females are the sole caregivers of their offspring. The female bilby mates iteroparously. Much of the plant diet of the bilby is facilitated by fires that occasionally run through Australian regions and facilitate the regrowth of plants that the bilby prefers. They are also a highly motile species when it comes to foraging, with females travelling on average 1.5 km between burrows and male travelling up to 5 km. The difference in male and female motility is most likely due to the fact that males are often in search of mates and need to only care for themselves, while females are responsible for their offspring and must work to support them. Communication remains difficult between bilbies due to poor eyesight, but since these marsupials usually live alone or in very small groups, this obstacle is not incredibly formidable. Any communication that does occur is mostly olfactory between males or auditory. The scent markings implemented by male bilbies primarily function as a mode of communication between members of the same sex, since female bilbies rarely take heed of such signals and males are never aggressive towards their female counterparts.
Greater bilbies are a vulnerable species, as classified by IUCN, their existence threatened by habitat loss and change as well as the competition with other animals. The main threats are cited as "Livestock farming & ranching" and "Invasive non-native/alien species/diseases". Introduced feral cats and foxes pose a major threat to the bilby's survival, and there is some competition between bilbies and rabbits for food. There is a national recovery plan for saving these animals: this program includes breeding in captivity, monitoring populations, and reestablishing bilbies where they once lived. The bilby has been popularised as a native alternative to the Easter Bunny by selling chocolate Easter Bilbies. Haigh's Chocolates in Adelaide made 950,000 chocolate bilbies between 1993 and Easter 2020, with proceeds donated to the Foundation for Rabbit-Free Australia (RFA), which does environmental work to protect the indigenous biodiversity of Australia. A National Bilby Day is held in Australia on the second Sunday in September to raise funds for conservation projects.
Reintroduction efforts have been successful in South Australia, with 16 bilbies released onto Thistle Island in 1997, and 9 released into the Arid Recovery Reserve near Roxby Downs in 2000. The Arid Recovery population's gene pool has been expanded by two additional releases in 2010 and 2020, the latter from the thriving population on Thistle Island. From 2001 to 2003, 19 bilbies were introduced into the Venus Bay Conservation Park at Venus Bay on the Eyre Peninsula. Bilbies have been bred at Monarto Zoo and (since 2009) at Cleland Conservation Park.
Bilbies were also introduced into the Currawinya National Park in Queensland, with six bilbies released into the feral-free sanctuary in early February 2006. In July 2012 it was reported that the population at Currawinya has been affected by feral cats that had gained access into the protected area after the wire netting had rusted after flooding. The high-salinity flood water had pooled around sections of the fencing, and once parts of it had rusted the cats had entered the reserve through the holes. Surveys found no bilbies in April nor July, when the cats were discovered.
Successful reintroductions have also occurred onto Peron Peninsula in Western Australia as a part of Western Shield. Successful reintroductions have also occurred on other conservation lands, including islands and the Australian Wildlife Conservancy's Scotia and Yookamurra Sanctuaries. There is a highly successful bilby breeding program at Kanyana Wildlife Rehabilitation Centre, near Perth.
A scientific description of the greater bilby was first published in 1837 by a Mr J. Reid. Reid based his description on a specimen that he erroneously stated to have come from Van Diemen's Land (now Tasmania), where the species has not occurred in historical times. As all bandicoot species were then placed in a broadly circumscribed Perameles, Reid placed the bilby there too. However, noting how different it was from other members of the genus, he added that "should more of the same form be discovered, the above characters would constitute a subgenus to which the name of Macrotis might be applied". The specific epithet lagotis was chosen "from its resemblance to the Rabbit".
The following year, Richard Owen read a paper before the Zoological Society of London, in which he proposed to erect a new genus for this species, named Thylacomys. This name was widely adopted and remained in use for many years. Thus it was that when B. Arthur Bensley erected a subfamily to hold the genus in 1903, he named it Thylacomyinae. This name remains valid, and has since been promoted to family rank as Thylacomyidae, but Thylacomys itself is no longer considered valid, as Reid's original paper is held to have established the generic name Macrotis. Thus the currently accepted scientific name for the species is Macrotis lagotis.
The placement of bilbies within the Peramelemorphia has changed in recent years. Vaughan (1978) and Groves and Flannery (1990) both placed this family within the family Peramelidae. Kirsch et al. (1997) found them to be distinct from the species in Peroryctidae (which is now a subfamily in Peramelidae). McKenna and Bell (1997) also placed it in Peramelidae, but as the sister of Chaeropus in the subfamily Chaeropodinae.
The term bilby is a loan word from the Yuwaalaraay Aboriginal language of northern New South Wales, meaning long-nosed rat. It is also known as dalgyte in Western Australia by the Noongar people. The Wiradjuri of New South Wales also call it bilby.
- Groves, C.P. (2005). "Order Peramelemorphia". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 38. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Burbidge, A.A & Woinarski, J. (2016). "Bilby: Macrotis lagotis". IUCN Red List of Threatened Species. 2016. doi:10.2305/IUCN.UK.2016-2.RLTS.T12650A21967189.en. Retrieved 28 October 2020.
Last assessed 15 June 2015CS1 maint: ref=harv (link) Database entry includes justification for why this species is listed as vulnerable.
- Reid, J. (1837). "Description of a new species of the genus Perameles (P. lagotis)". Proceedings of the Zoological Society of London. 1836: 129–131.
- Ellis, Richard (2005). No Turning Back: The Life and Death of Animal Species. New York: Harper Perennial. p. 224. ISBN 978-0-06-055804-8.
- "Greater Bilby". Arid Recovery. Retrieved 13 September 2020.
- Southgate, Richard; Possingham, Hugh (January 1995). "Modelling the reintroduction of the greater bilby Macrotis lagotis using the metapopulation model Analysis of the Likelihood of Extinction (ALEX)". Biological Conservation. 73 (2): 151–160. CiteSeerX 10.1.1.489.846. doi:10.1016/0006-3207(95)90041-1.
- "Mammals of the neighbourhood of Adelaide". South Australian Register (Adelaide, SA : 1839 - 1900). 17 November 1890. p. 3. Retrieved 11 September 2020.
- team, The Adelaide City Explorer. "Pinky Flat - Tarntanya Wama". Adelaide City Explorer. Retrieved 13 September 2020.
- "A Bandicoot in a Perth street". Nelson Advocate (WA : 1926 - 1938). 17 September 1926. p. 3. Retrieved 11 September 2020.
- "Bilby". AustralianAnimals.net. Archived from the original on 13 November 2010. Retrieved 30 December 2010.
- Gordon, Greg (1984). Macdonald, D. (ed.). The Encyclopedia of Mammals. New York: Facts on File. pp. 846–9. ISBN 978-0-87196-871-5.
- Jackson, Stephen (2007). Australian Mammals: Biology and Captive Management. CSIRO Publishing. ISBN 9780643095076.
- Southgate, R.; Christie, P.; Bellchambers, K. (2000). "Breeding biology of captive, reintroduced and wild greater bilbies, Macrotis lagotis (Marsupialia : Peramelidae". Wildlife Research. 27 (6): 621–628. doi:10.1071/wr99104.
- McDonald, Keith R; Dennis, Andrew J; Kyne, Peter M; Debus, Stephen JS; Curtis, Lee K (2012). Queensland's Threatened Mammals. CSIRO Publishing. ISBN 978-0643096141.
- "Macrotis lagotis in Species Profile and Threats Database". Canberra: Department of Sustainability, Environment, Water, Population and Communities. 2012. Retrieved 21 November 2012.
- Brown, E. "Macrotis lagotis: Reproduction". Animal Diversity Web.
- "Macrotis lagotis in Species Profile and Threats Database, Department of the Environment, Canberra". Department of Environment.
- "PSA: Haigh's Chocolates are available online. All. The. Time". CityMag. 29 March 2020. Retrieved 28 October 2020.
- "Save the Bilby Fund.com/". Retrieved 8 April 2011.
- "National Bilby Day 2019". Taronga Zoo. 6 September 2019. Retrieved 28 October 2020.
- Robinson, Lucy (18 July 2019). "Winter may be the best time to release captive-bred bilbies in southern Australia, research finds". ABC News. Australian Broadcasting Corporation. Retrieved 28 October 2020.
- Moseby, K. E.; O'Donnell, E.O. (2003). "Reintroduction of the greater bilby, Macrotis lagotis (Reid) (Marsupialia: Thylacomyidae), to northern South Australia: survival, ecology and notes on reintroduction protocols". Wildlife Research. 30: 15–27. doi:10.1071/WR02012.
- Lysaght, Gary-Jon (26 October 2020). "Bilbies released at Arid Recovery to boost population in outback SA". ABC News. Australian Broadcasting Corporation. Retrieved 27 October 2020.
- "Baby brings bilbies from brink". Adelaide Now. 27 January 2009. Retrieved 28 October 2020.
- "Save The Bilby Appeal". Queensland Government. 2004. Archived from the original on 24 October 2007.
- "Feral cats wreak havoc in raid on 'enclosed' refuge for endangered bilbies". Courier-Mail. 19 July 2012. Retrieved 18 September 2016.
- "Western Australian Department of Environment and Conservation 'Project Eden'". Archived from the original on 31 August 2007. Retrieved 27 August 2010.
- "Australian Wildlife Conservancy". Archived from the original on 23 May 2017. Retrieved 2 January 2020.
- Australian Wildlife Conservancy Scotia Sanctuary Archived 10 August 2008 at the Wayback Machine
- Australian Wildlife Conservancy Yookamurra Sanctuary Archived 9 May 2008 at the Wayback Machine
- "Kanyana Wildlife Rehabilitation Centre (Inc.)". Archived from the original on 29 June 2009. Retrieved 27 August 2010.
- Hausheer, Justine E. (15 July 2020). "Indigenous Knowledge Helps Map Habitat for the Threatened Bilby". The Nature Conservancy. Retrieved 28 July 2020.
- Southgate, R. I. (1990). "Distribution and abundance of the Greater Bilby Macrotis lagotis Reid (Marsupialia: Peramelidae)". In Seebeck, J. H.; Brown, P. R.; Wallis, R. L.; Kemper, C. M. (eds.). Bandicoots and Bilbies. Chipping Norton: Surrey Beatty & Sons. pp. 293–302. ISBN 978-0-949324-33-7.
- Groves, Colin; Flannery, Tim (1990). "Revision of the families and genera of bandicoots". Bandicoots and Bilbies. pp. 1–11.
- Reid, J. (January 1837). "Description of a new species of the genus Perameles (P. lagotis)". Proceedings of the Zoological Society of London. 5 (1): 129–131. doi:10.1111/j.1469-7998.1837.tb06823.x.
- Owen, Richard (1838). "[Thylacomys]". The Athenaeum: 747.
- Bensley, B. Arthur (1903). "On the evolution of the Australian Marsupialia microform : with remarks on the relationships of the marsupials in general". Transactions of the Linnean Society of London. 2. 9. Retrieved 18 September 2016.
- "Australian Words: A-B". Australian National University. 2005. Archived from the original on 18 February 2007. Retrieved 15 July 2010.
- Abbott, Ian (2001). "The Bilby Macrotis lagotis (Marsupialia: Peramelidae) in south-western Australia: original range limits, subsequent decline, and presumed regional extinction" (PDF). p. 35 (3 in PDF).
- Yokose, Hiroyuki (2001). "Aboriginal Words in Australian English" (PDF). p. 171 (3 in PDF).