The grayish mouse opossum (''Tlacuatzin canescens'') is a species of

opossum Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 93 species in 18 genera. Opossums originated in South America and entered North ...

endemic to Mexico. It is the sole species in the genus ''Tlacuatzin''.

Description

The grayish mouse opossum is an unusually small opossum, measuring in total length, including an 11- to 16-cm (4.3- to 6.3-in) tail. Adults weigh from . The body is covered in short, soft fur, with a slightly woolly texture. As the common name suggests, the fur is pale to brownish grey in colour, fading to white or near-white on the under parts and legs. In addition, clearly visible rings of black hair occur around the eyes, and, on females, patches of orange fur in the groin region, sometimes extending to the thighs and up the midline almost to the throat. The whiskers are relatively short, and the ears are rounded, hairless, and dark in colour. The tail is long and

prehensile Prehensility is the quality of an appendage or organ (anatomy), organ that has Adaptation (biology), adapted for grasping or holding. The word is derived from the Latin term ''prehendere'', meaning "to grasp". The ability to grasp is likely der ...

, and hairless for almost all of its length, apart from the base. Females have nine teats, but, unlike many other marsupials, do not have a pouch.

Distribution and habitat

It 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 ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

from southern

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...

Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the political divisions of Mexico, Federative Entities of Mexico. It is ...

, with populations also on the

Islas Marías The Islas Marías ("Mary Islands") are an archipelago of four islands that belong to Mexico. They are located in the Pacific Ocean, some off the coast of the mexican state, state of Nayarit and about southeast of the tip of Baja California. The ...

and in the central

Yucatán Peninsula The Yucatán Peninsula (, also , ; es, Península de Yucatán ) is a large peninsula in southeastern Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north ...

. It occupies seasonally arid

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s, especially mixed deciduous forests, but also scrub, grassland, and agricultural land. It has been reported up to elevations of , although it is more commonly found below . Two subspecies are currently recognised: * ''Tlacuatzin canescens canescens'' - Majority of range * ''Tlacuatzin canescens gaumeri'' - Yucatán Peninsula The main risks that threaten the Grayish mouse opossum is deforestation and competition with introduced species such as the Rattus rattus, known more commonly as the Black rat.https://enciclovida.mx/especies/33688-marmosa-canescens
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Biology and behaviour

The grayish mouse opossum is solitary and semi

arboreal Arboreal locomotion is the Animal locomotion, 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, but others are exclusively arboreal. Th ...

, being more terrestrial in its habits than other

mouse opossum The 27 species in the genus ''Marmosa'' are relatively small Neotropical members of the family Didelphidae. This genus is one of three that are known as mouse opossums. The others are ''Thylamys'' (the "fat-tailed mouse opossums") and '' Tlacuat ...

s. They have been reported to travel no more than between feeding sites, suggesting a small

home range A home range is the area in which an animal lives and moves on a periodic basis. It is related to the concept of an animal's territory which is the area that is actively defended. The concept of a home range was introduced by W. H. Burt in 1943. He ...

. Population densities have been reported to range from . The species has an omnivorous diet, but feeds mainly on insects such as bugs, cockroaches, moths, and beetles. It occasionally feeds on small lizards and bird eggs, and also feeds on fruit such as figs, coconuts, and oranges. Predators include

barn owl The barn owl (''Tyto alba'') is the most widely distributed species of owl in the world and one of the most widespread of all species of birds, being found almost everywhere except for the polar and desert regions, Asia north of the Himalaya ...

s and pumas. A nocturnal animal, the grayish mouse opossum spends the day in nests, generally in forks or hollows of trees, bushes or cacti, or in rock crevices. The nests are globular, constructed of leaves and stems, and lined with grass or plant fibres, such as the "cotton" obtained from kapok trees. It may also use the abandoned hanging nests of orioles or

wren Wrens are a family of brown passerine birds in the predominantly New World family Troglodytidae. The family includes 88 species divided into 19 genera. Only the Eurasian wren occurs in the Old World, where, in Anglophone regions, it is commonly ...

s. Breeding occurs in late summer and early autumn. The animals mate while hanging upside down from their tails, with the male tightly holding onto the female's neck with its jaws. The litter size ranges from 8 to 14. The young attach themselves to teats shortly after birth, and are sheltered by a pouch-like layer of hair, in the absence of a true pouch. The young leave the nest once they reach about in weight.

Parasites

Not many parasites have been recorded from the grayish mouse opossum. The pinworm ''Tlacuatzoxyuris simpsoni'' (

Nematoda The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broa ...

Oxyuridae Oxyuridae is a family of nematode worms of the class Secernentea. It consists of eight genera, one of which contains the human pinworm Pinworm infection (threadworm infection in the UK), also known as enterobiasis, is a human parasitic di ...

), a parasite of the cecum, has been described in 2019.

References

{{Taxonbar, from=Q784161 Opossums Endemic mammals of Mexico Marsupials of North America Fauna of Islas Marías Fauna of the Yucatán Peninsula Mammals described in 1893 Taxonomy articles created by Polbot Sinaloan dry forests Jalisco dry forests Fauna of the Southern Pacific dry forests