The golden-backed tree rat (''Mesembriomys macrurus'') is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

in the family

Muridae The Muridae, or murids, are either the largest or second-largest family of rodents and of mammals, containing approximately 870 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia. ...

, found only in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. Its native range was across

Northern Australia The unofficial geographic term Northern Australia includes those parts of Queensland and Western Australia north of latitude 26th parallel south, 26° and all of the Northern Territory. Those local government areas of Western Australia and Q ...

, but it has since become extinct from these regions. It is now only found in remote near-coastal areas in the

Kimberley Kimberly or Kimberley may refer to: Places and historical events Australia Queensland * Kimberley, Queensland, a coastal locality in the Shire of Douglas South Australia * County of Kimberley, a cadastral unit in South Australia Ta ...

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

. It is present in the

Charnley River–Artesian Range Wildlife Sanctuary Charnley River–Artesian Range Wildlife Sanctuary is a protected area covering about in the Kimberley region of Western Australia. It is situated about east of Derby and north west of Halls Creek, and is accessed via the Gibb River Road. It ...

Description

Golden-backed tree rats are named for their broad stripe of golden-coloured fur that runs from the top of its head to the base of their tail, of which has a white brush tip. They are

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

and

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

. During day, they sleep in their nests made in hollow trees, dense foliage or among rocks. They range in size from 18 to 34 cm with a 29 to 36 cm tail, and weigh 200-330 grams. Golden-backed tree rats are thought to breed throughout the year, with a gestation period of 48 days and litter size of 2. Their young are weaned at either six or seven weeks old. In captivity, the maximum longevity of a golden-back tree rat is 7.1 years.

Diet

The golden-backed tree rat forages mainly on fruits, travelling through areas with recently burnt vegetation to reach them. Their diet also consists of flowers, grasses and insects.

Range and habitat

The golden-backed tree rat is endemic to Australia. Its range is known to have included parts of the

Northern Territory The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regi ...

, where only three historical records of its presence in the territory is known. These being the upper McArthur River in 1901, upper Mary River in 1903, and in the Deaf Adder George of

Kakadu National Park Kakadu National Park is a protected area in the Northern Territory of Australia, southeast of Darwin. It is a World Heritage Site. Kakadu is also gazetted as a locality, covering the same area as the national park, with 313 people recorded l ...

in 1969. However, recent surveys have since failed to detect any signs of golden-backed tree rat populations in mainland NT. Local

Australian Aboriginal Aboriginal Australians are the various indigenous peoples of the Mainland Australia, Australian mainland and many of its islands, excluding the ethnically distinct people of the Torres Strait Islands. Humans first migrated to Australia (co ...

knowledge from the

Top End The Top End of Australia's Northern Territory is a geographical region encompassing the northernmost section of the Northern Territory, which aside from the Cape York Peninsula is the northernmost part of the Australian continent. It covers a ...

however suggests that the disappearance of golden-backed tree rats from the region occurred between the late 2000s and early 2010s. There is still however the possibility that the species is still present in the NT. In Western Australia, the golden-backed tree rat once had a range across parts of the

Pilbara The Pilbara () is a large, dry, sparsely populated regions of Western Australia, region in the north of Western Australia. It is known for its Indigenous Australians, Aboriginal people; wealth disparity; its ancient landscapes; the prevailing r ...

and the Kimberley.

Subfossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved i ...

of the species have been identified in the Pilbara, and the

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

originally came from near Roebourne in the Pilbara when the species was identified in 1875. During the 1800s in Broome, the golden-backed tree rat was once so common that it was considered a pest. When Norwegian zoologist

Knut Dahl Knut Dahl Knut Dahl (28 October 1871 – 11 June 1951) was a Norwegian zoologist and explorer who made important bird collections in northern Australia. Early years Dahl grew up at Hakadal in Akershus, Norway, where his father was an estate mana ...

visited Broome in 1896, he recorded that they raided bags of

rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...

and

flour Flour is a powder made by Mill (grinding), grinding raw grains, List of root vegetables, roots, beans, Nut (fruit), nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredie ...

around town. However, since 1903 all known records of the species have been from areas of the north-west Kimberley with higher rainfall, and their presence in the Pilbara and drier parts of the Kimberley have ended. The current distribution of golden-backed tree rats is restricted now to the north-west region of the Kimberley, approximately the area between Kalumburu to

Yampi Sound Yampi Sound is a part of the Indian Ocean off the coast of north-western Australia, in the Kimberley region of Western Australia. It is located between King Sound and Collier Bay. It lies between the Yampi Peninsula and the islands of the Bucca ...

. Here, it is found in the Artesian Range,

Mitchell Plateau Mitchell River National Park is a national park in the Kimberley region of Western Australia, northeast of Perth. The park adjoins the northern boundary of the Prince Regent National Park. The nearest towns are Derby, to the southwest, as wel ...

Prince Regent National Park Prince Regent National Park, formerly the Prince Regent Nature Reserve, is a protected area in the Kimberley region of Western Australia. In 1978 the area was nominated as a UNESCO World Biosphere Reserve. Land The national park covers a tota ...

, and Yampi Sound. It has also been found in areas of the

Wunaamin Miliwundi Ranges The Wunaamin Miliwundi Ranges (between 1879 and 2020 known as the King Leopold Ranges) are a range of hills in the western Kimberley region of Western Australia. There are two conservation parks within the ranges, the Wunaamin Conservation P ...

with suitable gorges in Central Kimberley. Its presence in the Mitchell Plateau is however recent, as it was first recorded there in 2012 after surveys between 2007 and 2012 found no results. This may suggest that golden-backed tree rats may be expanding locally. Golden-backed tree rat populations also occur on eleven islands off the Kimberley:

Augustus Gaius Julius Caesar Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian (), was the founder of the Roman Empire, who reigned as the first Roman emperor from 27 BC until his death in A ...

, Buckle Head, Carlia, Chambers, Conilurus, Hidden, Jar, Lachlan, Uwins, Wollaston, and an unnamed island in the Scott Strait. The current population of golden-backed tree rats is currently unknown.

Conservation

Status

On 3 July 2016, the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

assessed the golden-backed tree rat and listed it as being

near-threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to endangerment in the near future, but it does not currently qu ...

. Previously, the IUCN had ranked the species as being

least-concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wild ...

in 2008, and vulnerable in 1996. Under the

Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cult ...

, the species was listed in Australia as vulnerable from July 2000 to 2019 when it was delisted from the vulnerable category on 22 February by the

Minister for the Environment and Water The Australian Minister for the Environment and Water is a position which is currently held by Murray Watt in the Albanese ministry since 13 May 2025, following the Australian federal election in 2025. In the Government of Australia, the min ...

Melissa Price. Its conservation status in WA is vulnerable, while in the Northern Territory it is critically endangered.

Threats

The biggest threats to golden-backed tree rat populations are

feral cats A feral cat or a stray cat is an unowned domestic cat (''Felis catus'') that lives outdoors and avoids human contact; it does not allow itself to be handled or touched, and usually remains hidden from humans. Feral cats may breed over dozens ...

, and

bushfires A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a ...

. Bushfires are particularly harmful to the species when there is an increase in extensive hot fires in the late

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The t ...

. These fires destroy the tree hollows and foliage they nest in, and also decreases the number of fruiting vegetation they eat from. Golden-backed tree rats may also be threatened by introduced herbivores such as

cattle Cattle (''Bos taurus'') are large, domesticated, bovid ungulates widely kept as livestock. They are prominent modern members of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Mature female cattle are calle ...

, who the

Department of Climate Change, Energy, the Environment and Water The Department of Climate Change, Energy, the Environment and Water (DCCEEW) is a department of the Australian Government. The department was established on 1 July 2022, superseding the water and environment functions from the Department of A ...

state may alter "the availability of tall fruit bearing understorey shrubs" - an important food souce for golden-backed tree rats.

Protection

A 2015 government conservation advice approved by a delegate of the Minister for the Environment,

Greg Hunt Gregory Andrew Hunt (born 18 November 1965) is an Australian former politician who was the Minister for Health between January 2017 and May 2022. He was a Liberal Party member of the House of Representatives between November 2001 and 2022, repr ...

, listed several conservation actions to protect golden-backed tree rat populations. Actions given high priority were the development of "appropriate fire management in heKimberley", monitoring populations on the mainland and islands, and the involvement of Aboriginal rangers and communities in conservation efforts. Actions given medium priority were quarantining isolated island populations, and the reintroduction of golden-backed tree rats to the Northern Territory. The Charnely River-Artesian Range Wildlife Sanctuary contains and protects a significant population of the golden-backed tree rat, with the species being reasonably common in the sanctuary. The

Australian Wildlife Conservancy The Australian Wildlife Conservancy (AWC) is an independent Australian nonprofit organisation, working to conserve threatened wildlife and ecosystems in Australia. AWC is the largest private owner and manager of land for conservation in Austral ...

has also been active in the species' conservation, where it has collaborated with the

University of Tasmania The University of Tasmania (UTAS) is a public research university, primarily located in Tasmania, Australia. Founded in 1890, it is Australia's fourth oldest university. Christ College (University of Tasmania), Christ College, one of the unive ...

to investigate the effect of fires on them.

In culture

The indigenous Wunambal people have traditionally used the tails of golden-backed tree rats to make special necklaces.

Name

Golden-backed tree rats are known as ''Koorrawal'', ''Wunggangbarn'', or ''Jari'' in

Wunambal The Wunambal (Unambal), also known as Wunambal Gaambera, Uunguu (referring to their lands), and other names, are an Aboriginal Australian people of the northern Kimberley region of Western Australia. People The Wunambal were, according to Norma ...

, and in the Yiiji dialect of Wunambal spoken by the Yeidji people, it is called ''Jari Manya''. A synonym for ''Mesembriomys macrurus'' is ''Hapalotis boweri'', named by

Edward Pierson Ramsay Edward Pierson Ramsay (3 December 1842 – 16 December 1916) was an Australian zoologist who specialised in ornithology. Early life Ramsay was born in Dobroyd Estate, Long Cove, Sydney, and educated at St Mark's Collegiate School, The King's S ...

in 1887 when he incorrectly identified specimens forwarded by his friend and colleague Thomas Henry Boyer-Bower as a new species. Ramsay named ''Hapalotis boweri'' in honour of Boyer-Bower who had recently died.

References

* {{Taxonbar, from=Q1765881 Mesembriomys Mammals of Western Australia Mammals of the Northern Territory Rodents of Australia Vulnerable fauna of Australia Mammals described in 1876 Taxonomy articles created by Polbot Taxa named by Wilhelm Peters