By Jill Ceitlin
Geographic Range
Neotoma mexicana, or Mexican woodrats, is found in the Southwestern United States from northern Colorado and southern Utah down through Arizona, New Mexico, Oklahoma, and Texas and into Central Mexico and Guatemala. ("eNature", 2003; "Natural Diversity Information Source", 2004; "Oklahoma Museum of Natural History Mammal Key", 1989; "Utah Division of Wildlife Resources", 2004; Meaney and Armstrong, 1994; Wilson and Ruff, 1999)
Biogeographic Regions:
nearctic 
(native ); neotropical .
Habitat
(49.2 to 13202 ft)
Neotoma mexicana lives in rocky areas and normally builds nests in the cracks and crevices of canyon walls or boulders. Nests are also found in hollow trees or abandoned buildings. Mexican woodrats live mostly in mountainous areas, but can also be found in deciduous forests. One of the most common types of woodlands they are found in is piñon-juniper. Their elevation ranges from 15 to 4025 meters. Because they use cracks in rocky slopes, their dens are not very elaborate. They do, however, still accumulate sticks and other rubbish around their dens. Dens can sometimes be located by noticing fecal pellets because Neotoma mexicana defecates near its nest. ("Oklahoma Museum of Natural History Mammal Key", 1989; Cornely and Baker, 1986; Davis and Schmidly, 1997; Wilson and Ruff, 1999)
These animals are found in the following types of habitat:
temperate ; tropical ; terrestrial .
Physical Description
(4.93 to 6.51 oz)
(11.42 to 16.42 in; avg. 11.81 in)
Neotoma mexicana is grayish to brownish on its back and its underside is buff to white. It can be distinguished from desert woodrats because the tail has two distinct colors. It is brown on top and white on the bottom. The average body length of Neotoma mexicana is 300 mm and the average tail length is 125 mm. At birth, the animal weighs 9-12 grams and reaches 140-185 grams as an adult. ("eNature", 2003; "Utah Division of Wildlife Resources", 2004; Davis and Schmidly, 1997; Davis, 1960; Meaney and Armstrong, 1994; Wilson and Ruff, 1999)
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
Mexican woodrats will usually have two litters per breeding season.
Breeding occurs from March through May and may last longer in the southern part of the range.
Not much is known about the mating systems of the Mexican woodrat. Agonistic behavior has been observed in the laboratory setting during mating. Also, males may make a gasping sound when approaching a female to mate. (Meaney and Armstrong, 1994)
Mexican woodrats breed from March until May and usually produces two litters during that time. Each litter can have 2-5 pups, and the gestation period is about 33 days. The young are weaned anywhere from 4-6 weeks after birth. Females reach sexual maturity at a younger age than males. After 1-2 months, females can reach sexual maturity and even produce their own litters during that same breeding season. On the other hand, males reach sexual maturity at around 8 months. Also, Neotoma mexicana experiences a post-partum estrus. ("eNature", 2003; "Utah Division of Wildlife Resources", 2004; Davis and Schmidly, 1997; Davis, 1960; Meaney and Armstrong, 1994; Wilson and Ruff, 1999)
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous ; post-partum estrous.
The young are found in a nest along with either an adult male or adult female, not both. Not much is known about the care or investment provided by the parents, but these animals are born underdeveloped and reach sexual maturity at 2 months for females and 9 months for males. The time of weaning is 4-6 weeks. ("eNature", 2003; Davis, 1960; Wilson and Ruff, 1999)
Parental investment:
altricial .
Lifespan/Longevity
The lifespan of this species is not known.
Behavior
Neotoma mexicana is a solitary species and can be aggressive towards conspecifics. It collects many items such as sticks, feathers, and bones and therefore has received the common name of packrat. It is active year around and usually at night. ("Oklahoma Museum of Natural History Mammal Key", 1989; Meaney and Armstrong, 1994; Wilson and Ruff, 1999)
Home Range
Woodrats have a home range of about 20 to 25 yards from the den. (Palmer, 1954)
Key behaviors:
terricolous; nocturnal ; motile ; solitary ; territorial .
Communication and Perception
In general, woodrats communicate with squeals, and warning signals are made by thumping the hind feet and vibrating the tail. Gasping or chirping sounds are made during mating. Scentmarking by rubbing the ventral side and foot-thumping is also common in Neotoma mexicana as a means of communicating. (Cornely and Baker, 1986; Palmer, 1954)
Other communication keywords:
vibrations .
Perception channels:
visual ; tactile ; vibrations ; chemical .
Food Habits
Neotoma mexicana forages on the ground or may climb like other woodrats. This species is a dietary generalist and eats nuts, berries, green vegetation, acorns, and fungi. They sometimes store their food. ("eNature", 2003; "Natural Diversity Information Source", 2004; "Utah Division of Wildlife Resources", 2004; Davis and Schmidly, 1997; Meaney and Armstrong, 1994; Palmer, 1954; Wilson and Ruff, 1999)
Plant Foods:
leaves; seeds, grains, and nuts; fruit.
Other Foods:
fungus.
Foraging Behaviors:
stores or caches food .
Predation
- owls (Strigiformes)
- foxes (Canidae)
- coyotes (Canis latrans)
- bobcats (Lynx rufus)
- weasels (Mustela)
- rattlesnakes (Crotalidae)
The known predators of Mexican woodrats are owls, foxes, coyotes, weasels, rattlesnakes, and bobcats. There are no anti-predator adaptations known for this species. (Ward and Ganey, 2003; Wilson and Ruff, 1999)
Ecosystem Roles
Neotoma mexicana is an important source of prey for owls, foxes, coyotes, bobcats, weasels and rattlesnakes. They also disperse seeds. (Peterson et al., 2002; Ward and Ganey, 2003; Wilson and Ruff, 1999)
Key ways these animals impact their ecosystem:
disperses seeds.
Economic Importance for Humans: Negative
Neotoma mexicana is known to be one of the hosts of Chagas disease. One strain of the disease coincides with the distribution of the Mexican woodrat. It is transmitted through blood and causes infection in the organs and peripheral nervous system. Usually, the disease is transmitted by blood feeding insects. Neotoma mexicana is also a carrier of the arroyo virus, one that attacks the central nervous system. (Fulhorst et al., 2001; Peterson et al., 2002)
Ways that these animals might be a problem for humans:
injures humans (carries human disease).
Economic Importance for Humans: Positive
Although it is not documented as a common ocurrance, Mexican woodrats may serve as food for humans. (Davis, 1960)
Ways that people benefit from these animals:
food .
Conservation Status
IUCN Red List: [link]:
Lower Risk - Least Concern.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
This species does not have a conservation status because it is not threatened.
For More Information
Find Neotoma mexicana information at
Contributors
Matthew Wund (editor), University of Michigan.
Jill Ceitlin (author), University of Michigan. Phil Myers (editor, instructor), Museum of Zoology, University of Michigan.
