Maclear's rat (''Rattus macleari'') is an extinct large

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...

endemic Endemism is the state of a species being found only 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 foun ...

Christmas Island Christmas Island, officially the Territory of Christmas Island, is an States and territories of Australia#External territories, Australian external territory in the Indian Ocean comprising the island of the same name. It is about south o ...

in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

. It was one of two species of rat native to Christmas Island, alongside the bulldog rat. Abundant, unfamiliar with and seemingly unafraid of humans, large numbers of the creatures emerged and foraged in all directions at night. Making querulous squeaks, the rats entered the ''Challenger'' expedition's

tent A tent is a shelter consisting of sheets of fabric or other material draped over or attached to a frame of poles or a supporting rope. While smaller tents may be free-standing or attached to the ground, large tents are usually anchored using g ...

s and shelters in 1886, ran over sleepers, and upset everything in the search and fight for food. Maclear's rat might have been responsible for keeping the population of the Christmas Island red crab in check, as recent numbers of the crab are greater than in the past. It is thought that

black rat The black rat (''Rattus rattus''), also known as the roof rat, ship rat, or house rat, is a common long-tailed rodent of the stereotypical rat genus ''Rattus'', in the subfamily Murinae. It likely originated in the Indian subcontinent, but is n ...

s inadvertently introduced by the expedition infected the Maclear's rats with a disease (possibly a trypanosome), which in turn could have contributed to the species' decline. The last recorded sighting was in 1903, although it is possible that Maclear's rats hybridized with black rats. A hard tick ('' Ixodes nitens''), described as an

ectoparasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

of Maclear's rat, is also thought to be extinct. MaclearsRatSkull

Said to be related to '' Rattus xanthurus'' of Sulawesi and '' R. everetti'' of the Philippines, this species was grizzled brown above and lighter on the underside. The lower back had prominent long and black hairs that projected above the shorter fur. The base of the tail was dark with the distal half being scaly white. MaclearsRat-PLoSOne

The rat is named after Captain John Maclear (1838–1907) of the British survey-ship HMS ''Flying-Fish'', who collected the specimen from Christmas Island in 1886. It was described as a new species by

Oldfield Thomas Michael Rogers Oldfield Thomas (21 February 1858 – 16 June 1929) was a British zoologist. Career Thomas worked at the Natural History Museum, London, Natural History Museum on mammals, describing about 2,000 new species and subspecies for ...

the next year, although it was originally described under the genus '' Mus''. Maclear was earlier commander on HMS ''Challenger'' for the ''Challenger'' Expedition of 1872–1876 under its commission captain, Sir George Nares. A DNA study found Maclear's rat to be the sister species of Hainald's rat native to the island of

Flores Flores is one of the Lesser Sunda Islands, a group of islands in the eastern half of Indonesia. Administratively, it forms the largest island in the East Nusa Tenggara Province. The area is 14,250 km2. Including Komodo and Rinca islands ...

, with the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

containing the two being sister to the clade containing '' Nesokia'' and ''

Bandicota ''Bandicota'' is a genus of rodents from Asia known as the bandicoot rats. Their common name and genus name are derived from the Telugu language word ''pandikokku'' (పందికొక్కు). DNA studies have found the group to be a monop ...

''; this clade, in turn, is sister to the Australasian ''

Rattus ''Rattus'' is a genus of muroid rodents, all typically called rats. However, the term rat can also be applied to rodent species outside of this genus. Species and description The best-known ''Rattus'' species are the black rat (''R. rattus'') ...

'' radiation, making ''Rattus'' as currently defined

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

Potential revival

In March 2022, researchers discovered that Maclear's rat shared about 95% of its genes with the living

brown rat The brown rat (''Rattus norvegicus''), also known as the common rat, street rat, sewer rat, wharf rat, Hanover rat, Norway rat and Norwegian rat, is a widespread species of common rat. One of the largest Muroidea, muroids, it is a brown or grey ...

, thus sparking ideas of bringing the species back to life. Although scientists were mostly successful in using CRISPR technology to edit the DNA of the brown rat to match that of Maclear's, a few key genes were missing, which would mean that the resurrected Maclear's rats would not be genetically pure replicas and would lack critical components such as scent and immunities.

References

{{Taxonbar, from=Q674054 Rattus Rodent extinctions since 1500 Extinct animals of Australia Fauna of Christmas Island Mammals described in 1887 Taxa named by Oldfield Thomas Species that are or were threatened by disease Species that are or were threatened by invasive species

Potential revival

See also

References