The central rock rat (''Zyzomys pedunculatus''), also known as the central thick-tailed rock-rat, Macdonnell Range rock-rat, and Australian native mouse,
is a
Critically Endangered species of
rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are nat ...
in the family
Muridae
The Muridae, or murids, are the largest family of rodents and of mammals, containing approximately 1,383 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia.
The name Muridae comes ...
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
to
Australia.
Description
The central rock-rat is one of five rock-rat species native to Australia. It is a
nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
species that specifically forages for food in the nighttime.
[Central Rock Rat]
Animal Info They can range from 10.6 to 14.9 cm long for the head and body, and around 30 cm from head to tail.
. earthsendangered.com They weigh between 50 and 120 g.
Their fur is a light mustard above with a pale underbelly. The lightly furred tail is the most noticeable feature of the central rock-rat. The tail base is thick and bulky. The thickness of the tail has been reported to be a fat storage adaptation. This is an effect of scarce food distribution. Rock-rats are known to lose their tails, fur and skin very easily and are, therefore, known to be difficult to handle.
[Cole, Jeff (2000]
National recovery plan for the Central Rock-rat (''Zyzomys pedunculatus'')
Parks and Wildlife Commission of the Northern Territory, Environment Australia As for their birthrate, captive animals have bred and have had litters of various sizes, ranging from one to four young.
[
]
Distribution and habitat
The rats have been found in rocky outcrops and on mountainsides with loose stones, as well as hilly grasslands and low open shrubland or woodland. Historically, the central rock rat is only known to be found in a 77 km length of the West MacDonnell Ranges, Northern Territory. The species has previously been recorded from living animals or cave deposits in Northern Territory at Uluru-Kata Tjuta National Park, Illamurta (James Range), Haasts Bluff
Haasts Bluff, also known as Ikuntji, is an Aboriginal Australian community in Central Australia, a region of the Northern Territory. The community is located in the MacDonnell Shire local government area, west of Alice Springs. At the 2006 ce ...
(West MacDonnell Ranges), Mount Liebig
Mount Liebig is a mountain with an elevation of in the southern part of the Northern Territory of Australia. It is one of the highest peaks of the MacDonnell Ranges and was named by the explorer Ernest Giles after the German chemist Justus vo ...
, Napperby Station
Napperby Station, also known as Napperby, is a pastoral lease used as a cattle station in the Northern Territory of Australia.
History
The station was established on Anmatyerre tribal land. The Chisholm family have owned Napperby Station "on ...
, Devils Marbles, The Granites (Tanami Desert), and the Davenport Range National Park. It is known from cave deposits in the Cape Range National Park
Cape Range National Park is a national park in the Gascoyne region of Western Australia, north of Perth. The park occupies the western side of the North West Cape peninsula over an area of . The nearest town is Exmouth. Directly off the coast ...
.
Believed extinction
The species was believed to have been extinct in both 1990 and 1994 due to population decline. In 2001 individuals were trapped from fourteen locations, but in 2002 drought and wildfire struck the area and the species was not recorded after that. It has been classed as Critically Endangered by the IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...
. In 2013 they were also discovered by motion-sensor cameras on the Haasts Bluff Aboriginal Land Trust, west of Alice Springs
Alice Springs ( aer, Mparntwe) is the third-largest town in the Northern Territory of Australia. Known as Stuart until 31 August 1933, the name Alice Springs was given by surveyor William Whitfield Mills after Alice, Lady Todd (''née'' Al ...
.
Ecology
The diet of the central rock rat consists of four major food groups that can be found across all seasons. Seed makes up 72% of the species food intake. The rest of its diet consist of plant leaves (21%), plant stems (3%), and insects (4%). They can be found near rocky habitats for burrow sites and local seed availability. This helps to explain why the central rock rat is found in such scarce numbers, since they rely on constant food supply and a steady and supportive habitat. This makes locating the central rock rat difficult to find in the Central Australian range. They play an essential role in seed dispersal as well as food resource for other animals in the wild. The species likely has a pattern of recovery and expansion during wet periods, probably due to increased food supply.
Conservation
Threats
Habitat degradation is an obstacle to Central rock rat conservation. Fires limit the available habitat, and the spread of Buffalo grass kills off native grasses that central the rock rat feeds on and helps contribute to the spread of fire. They face predators such as dingo
The dingo (''Canis familiaris'', ''Canis familiaris dingo'', ''Canis dingo'', or ''Canis lupus dingo'') is an ancient ( basal) lineage of dog found in Australia. Its taxonomic classification is debated as indicated by the variety of scient ...
s, and grazing from feral herbivores hurts their food supply. Despite all this, the species is believed to be making strides, which is supported by the sightings near the Haasts Bluff
Haasts Bluff, also known as Ikuntji, is an Aboriginal Australian community in Central Australia, a region of the Northern Territory. The community is located in the MacDonnell Shire local government area, west of Alice Springs. At the 2006 ce ...
Aboriginal land trust west of Alice Springs, in Australia. The rat's predators can also give insight on how the species is recovering. The excrement of feral cats near the location site often includes the fur and bone skeletons of the central rock rat. Until the 1996 capture, the central rock-rat had not been seen since 1960. Between 1970 and 1995, there were no recorded sightings of the species and it was declared that this species was indeed extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
. It wasn't until it was rediscovered in 1996 in the MacDonnell Ranges
The MacDonnell Ranges, or Tjoritja in Arrernte, is a mountain range located in southern Northern Territory. MacDonnell Ranges is also the name given to an interim Australian bioregion broadly encompassing the mountain range, with an area of . ...
that this was proven false. On September 3, 1996, members of the Conservation Volunteers Australia trapped an animal which was later identified from photographs as the central rock-rat. Since that time sub-populations have been found at 15 other sites over a small area of the West MacDonnell Ranges. The full range of the current distribution of the species is unknown.
Legislation and plans
The Central rock rat has a national recovery plan through the Australian government, its overall objective being to stabilize the species and prevent population decreases. Specific objectives include: clarifying distribution, population size, and habitat; to create and employ management strategies of the sub-populations; maintaining captive populations; investigating the biology of captive individuals; and to increase awareness in the community. Recovery actions include establishing the sizes of sub-populations and monitoring changes in them, creating a fire strategy for known population locations, and capturing animals to add to the captive breeding
Captive breeding, also known as captive propagation, is the process of plants or animals in controlled environments, such as wildlife reserves, zoos, botanic gardens, and other conservation facilities. It is sometimes employed to help species tha ...
program. The recovery plan also has a provision for habitat protection which would help other native species such as the common brushtail possum
The common brushtail possum (''Trichosurus vulpecula'', from the Greek for "furry tailed" and the Latin for "little fox", previously in the genus ''Phalangista'') is a nocturnal, semiarboreal marsupial of the family Phalangeridae, native to Aust ...
and the black-flanked rock-wallaby. Beginning in 1996, after the re-discovery of the central rock-rat, a captive breeding program was set up at Alice Springs Desert Park and at the Perth Zoo. After initially introducing 14 individuals from the wild, the first generation bred successfully but the subsequent one had significant trouble, eventually leading to the death of the last male in 2011.
The National Recovery Plan for the Central Rock-rat in 2017 suggested to attempt another breeding program during a natural irruption phase of the wild population, for example after the heavy rainfall in the winter of 2016, so as to limit the effects on the wild numbers of the species.
References
External links
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{{Taxonbar, from=Q1766478
Zyzomys
Critically endangered fauna of Australia
Mammals of the Northern Territory
Rodents of Australia
Mammals described in 1896
Taxonomy articles created by Polbot