Hatt's vesper rat (''Otonyctomys hatti''), also known as Hatt's vesper mouse or Yucatán vesper rat, 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 ...

in the family

Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, and has m ...

. It is the only species in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Otonyctomys''. It is named for its discoverer, Robert T. Hatt.

Description

Hatt's vesper rat has a typical

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'' (bandicoot ...

-like appearance, and closely resembles the related

Sumichrast's vesper rat Sumichrast's vesper rat (''Nyctomys sumichrasti'') is a rodent of the family Cricetidae found from southern Mexico to Panama. It is named for the collector of the first specimen, and its closest relative is probably Hatt's vesper rat, a similar, ...

, from which it can most easily be distinguished by its much larger

auditory bulla The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal. It originates as a separate bone (tympanic ...

e. It is relatively small for a rat, both sexes having a head body length of , and a long, , tail. Adults weigh from . The rat is brightly coloured, with bright russet or yellowish fur over most of the body, and creamy or white underparts. The face has a short, rounded snout, and conspicuous black markings in front of the eyes, stretching as far as the

whiskers Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to touch, sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are c ...

. Younger individuals tend to be duller in colour, and have less glossy fur than the adults. The tail is thickly covered with brown fur along its entire length, although the ears are largely hairless. Females have four abdominal

teat A teat is the projection from the mammary glands of mammals from which milk flows or is ejected for the purpose of feeding young. In many mammals the teat projects from the udder. The number of teats varies by mammalian species and often corre ...

Distribution and habitat

Hatt's vesper rat is found throughout the

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 ...

, in the Mexican states of

Campeche Campeche (; yua, Kaampech ), officially the Free and Sovereign State of Campeche ( es, Estado Libre y Soberano de Campeche), is one of the 31 states which make up the 32 Federal Entities of Mexico. Located in southeast Mexico, it is bordered by ...

Yucatán Yucatán (, also , , ; yua, Yúukatan ), officially the Free and Sovereign State of Yucatán,; yua, link=no, Xóot' Noj Lu'umil Yúukatan. is one of the 31 states which comprise the political divisions of Mexico, federal entities of Mexico. I ...

, and

Quintana Roo Quintana Roo ( , ), officially the Free and Sovereign State of Quintana Roo ( es, Estado Libre y Soberano de Quintana Roo), is one of the 31 states which, with Mexico City, constitute the 32 federal entities of Mexico. It is divided into 11 mu ...

, and in northern

Guatemala Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...

and

Belize Belize (; bzj, Bileez) is a Caribbean and Central American country on the northeastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a wate ...

. It inhabits broadleaf tropical forests close to water and below about elevation. It has generally been recorded in trees or

liana A liana is a long- stemmed, woody vine that is rooted in the soil at ground level and uses trees, as well as other means of vertical support, to climb up to the canopy in search of direct sunlight. The word ''liana'' does not refer to a ta ...

s, on fallen wood, or even in the rafters of houses, and may be largely arboreal in its habits.

Biology

The rat is little studied, and, as of 2008, was known only from eighteen specimens. It appears to be nocturnal, and herbivorous, eating seeds and fruit, and to spend much of its time in the trees. The breeding season, if it has a specific one, is unknown, although one specimen caught in February was a lactating female. It is listed as a threatened species in Mexico, but is considered of

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

by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

because of its apparently wide distribution and adaptability. Fossil specimens have been discovered dating back to the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

References

{{Taxonbar, from=Q40642 Mammals described in 1932 Rodents of Central America Tylomyinae Taxonomy articles created by Polbot