Sumichrast's vesper rat (''Nyctomys sumichrasti'') is a
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 ...
of 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 over 870 species, it is either the largest or second-largest family ...
found from southern
Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
to
Panama
Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...
. It is named for
François Sumichrast, the collector of the first specimen, and its closest relative is probably
Hatt's vesper rat, a similar, but slightly smaller, species from the
Yucatán Peninsula
The Yucatán Peninsula ( , ; ) is a large peninsula in southeast Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north and west of the peninsula from the C ...
.
[
]
Description
Sumichrast's vesper rat is a relatively small rat, with an adult length of , not including the tail, which is only slightly shorter. Males and females are of similar size, with both weighing between . It is one of the more brightly coloured rats, with a reddish or orange back and creamy to white underparts. The rats have a thick pelt of soft fur, which extends over the entire length of the tail, and is absent only on the soles of the feet. The eyes are relatively large, and surrounded by a narrow ring of black hair, while the whiskers are long and the ears small.
To aid in climbing, the claws are compressed and curved, and the first toe on each foot is thumb-like.
Distribution and subspecies
Sumichrast's vesper rat is found from southern Jalisco and Veracruz in Mexico through much of Central America, excluding the Yucatan, as far east as central Panama
Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...
. It occurs in evergreen and semi-deciduous forests throughout this range, at elevations from sea level to as high as .[ A total of nine subspecies are currently recognised:][
* ''N. s. sumichrasti'' - southern ]Veracruz
Veracruz, formally Veracruz de Ignacio de la Llave, officially the Free and Sovereign State of Veracruz de Ignacio de la Llave, is one of the 31 states which, along with Mexico City, comprise the 32 Political divisions of Mexico, Federal Entit ...
, Mexico
* ''N. s. colimensis'' - Jalisco
Jalisco, officially the Free and Sovereign State of Jalisco, is one of the 31 states which, along with Mexico City, comprise the 32 Political divisions of Mexico, Federal Entities of Mexico. It is located in western Mexico and is bordered by s ...
to Oaxaca
Oaxaca, officially the Free and Sovereign State of Oaxaca, is one of the 32 states that compose the political divisions of Mexico, Federative Entities of the Mexico, United Mexican States. It is divided into municipalities of Oaxaca, 570 munici ...
, Mexico
* ''N. s. costaricensis'' - southern Costa Rica
Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...
* ''N. s. decolorus'' - southern Belize
Belize is a country on the north-eastern 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 maritime boundary with Honduras to the southeast. P ...
and eastern Guatemala
Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...
to Honduras
Honduras, officially the Republic of Honduras, is a country in Central America. It is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, ...
* ''N. s. florencei'' - southern Honduras and western Nicaragua
Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...
* ''N. s. nitellinus'' - eastern Costa Rica
Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...
to central Panama
Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...
* ''N. s. pallidulus'' - southern Tabasco
Tabasco, officially the Free and Sovereign State of Tabasco, is one of the Political divisions of Mexico, 32 Federal Entities of Mexico. It is divided into Municipalities of Tabasco, 17 municipalities and its capital city is Villahermosa.
It i ...
and western Chiapas
Chiapas, officially the Free and Sovereign State of Chiapas, is one of the states that make up the Political divisions of Mexico, 32 federal entities of Mexico. It comprises Municipalities of Chiapas, 124 municipalities and its capital and large ...
* ''N. s. salvini'' - eastern Chiapas and southern Guatemala
* ''N. s. venustulus'' - eastern Nicaragua
Biology and behaviour
Sumichrast's vesper rat is unusual in that it is 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 ...
, and builds nests of twigs and leaves. They rarely travel along the ground, preferring to remain in the middle and upper parts of the forest canopy, between high. They build their nests in tree hollows or in the forks of branches, constructing an irregular mass of material with a hollow central cavity about across, often building them on top of older nests so that a series of multiple layers builds up over time.[
It is ]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 herbivorous, eating fruits and seeds, although it has been reported to eat a small number of moth
Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...
s. Favoured foods include figs, and the seeds of plants such as '' Jacquinia pungens'' and borage
Borage ( or ; ''Borago officinalis''), also known as starflower, is an annual herb in the flowering plant family Boraginaceae native to the Mediterranean region. Although the plant contains small amounts of pyrrolizidine alkaloids, some parts ar ...
.[ In Costa Rica, they have also been observed to eat the poisonous leaves of the plant '' Daphnopsis americana'', although avoiding the central part of the leaf, and selecting only young leaves.] They follow established paths along branches in search of food, and have a 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. ...
of about across. Although they move slowly when compelled to travel along the ground, and make slow deliberate movements while feeding or grooming, they are agile in the trees, moving rapidly and constantly twitching their whiskers and ears.[
Under laboratory conditions, the rats remain in family groups of mated pairs, but are intolerant of any strangers, often attacking them. They have been observed to make high-pitched, musical chirps and trills, while males sometimes make lower pitched grunts towards established mates.]
Reproduction
Mating occurs throughout the year.[ Gestation lasts from 30 to 38 days and results in the birth of one to three young. The young are reared in a nest constructed by both parents, although the male usually remains outside the nest for the first seven days after birth. The young are about long at birth, and weigh . They are initially blind and only partially furred, and remain attached to the mother's teats for most of their first two weeks, although they are able to crawl from two days of age. They are weaned at around three weeks, and their eyes open after fifteen to eighteen days.][
The rats become sexually mature at around 75 days of age,][ and have lived for up to five years in captivity.][
]
References
*Clutton-Brock, Juliet (ed.). 2004. Mouse-like Rodents. pp150–159 in ''Animal'' (David Burnley ed.). London, Dorling Kindersley.
{{Authority control
Tylomyinae
Rodents of Central America
Mammals described in 1860