The Galápagos rice rat (''Aegialomys galapagoensis''), also known as the Galápagos oryzomys, is a 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 na ...

that is

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 elsew ...

to the

Galápagos Islands The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...

Description

The Galapagos rice rat is a medium-sized rodent, with a head-body length of , and a tail long. It has very long, soft and dense fur that is grizzled copper-brown above and yellowish-grey on the underparts. The ears are long and covered with dense hair, and the feet have large pads on the soles, with claws up to in length, suggesting that it has little, if any, climbing ability.

Distribution and habitat

The Galapagos rice rat is found only in the eastern Galapagos. Today, it occurs only on

Santa Fé Island Santa Fe Island (Spanish: ''Isla Santa Fe''), also called Barrington Island after admiral Samuel Barrington, is a small island of which lies in the centre of the Galápagos archipelago, to the south-east of Santa Cruz Island. Visitor access i ...

, and possibly on Santiago Island. A separate population formerly existed on

San Cristóbal Island San Cristóbal Island ( es, Isla San Cristóbal) and named previously by the English as ''Chatham Island'', is the easternmost island in the Galápagos archipelago, as well as one of the oldest geologically. It is administratively part ...

, and is considered to represent a separate subspecies, but is thought to have been extinct for many decades. Its natural habitat is subtropical or tropical dry

shrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity. It m ...

Biology and behaviour

The Galapagos rice rat is primarily nocturnal, but may sometimes be active before sunset, spending the day resting in crevices beneath lava blocks or under shrubs. It is omnivorous, feeding on plant matter and insects. Like many of the animals of the Galápagos, it is tame and unafraid of humans. Scientists working on Santa Fé Island and

Fernandina Island Fernandina Island (Spanish: ''Isla Fernandina'', named after King Ferdinand of Spain, the sponsor of Christopher Columbus) (formerly known in English as Narborough Island, after John Narborough) is the third largest, and youngest, island of the ...

have reported that it is necessary to keep tents open to prevent these rice rats from chewing in during the night. It is also commonly seen on beaches, where it is attracted by fish remains left behind by human activity. Breeding seems to take place primarily in the hot season with young being born between March and May, but may occur at other times of year, perhaps depending on the availability of food resources. Litters of 2–7 young are born hairless and blind, opening their eyes and developing the adult coat by day 13 after birth. The maximum lifespan in the wild has been recorded as 599 days.

Taxonomy

The species was previously placed in ''

Oryzomys ''Oryzomys'' is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which—the marsh rice rat (''O. palustris'') of the United States and ...

'' as ''Oryzomys galapagoensis''. The

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

''A. g. bauri'' from Santa Fé Island is sometimes considered to represent a full species. ''A. g. galapagoensis'' was formerly found on

, where

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...

captured several live specimens on the

second voyage of HMS Beagle The second voyage of HMS ''Beagle'', from 27 December 1831 to 2 October 1836, was the second survey expedition of HMS ''Beagle'', under captain Robert FitzRoy who had taken over command of the ship on its first voyage after the previous capta ...

in 1855. However, it is believed that it became extinct only decades after Darwin's visit, and the next specimens collected were subfossil remains found in lava tubes by

David Steadman David William Steadman is a paleontologist and ornithologist, and serves as the curator of ornithology at the Florida Museum of Natural History at the University of Florida. His research has concentrated on the evolution, biogeography, conservation ...

and colleagues in 1984. Its closest relative is ''

Aegialomys xanthaeolus ''Aegialomys xanthaeolus'', also known as the yellowish oryzomys or yellowish rice rat, is a species of rodent in the family Cricetidae. It belongs to the genus ''Aegialomys'' in tribe Oryzomyini, which was not recognized as distinct from ''Oryzom ...

'', the only other species in the genus, which is found in coastal Ecuador and Peru.

References

{{Taxonbar, from=Q507366 Aegialomys Endemic fauna of the Galápagos Islands Mammals described in 1839 Taxonomy articles created by Polbot