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Neotoma mexicanaMexican woodrat

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)

Habitat

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)

  • Range elevation
    15 to 4025 m
    49.21 to 13205.38 ft

Physical Description

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)

  • Range mass
    140 to 185 g
    4.93 to 6.52 oz
  • Range length
    290 to 417 mm
    11.42 to 16.42 in
  • Average length
    300 mm
    11.81 in

Reproduction

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. (Davis and Schmidly, 1997; Meaney and Armstrong, 1994; "eNature", 2003; "Utah Division of Wildlife Resources", 2004; Davis and Schmidly, 1997; Davis, 1960; Meaney and Armstrong, 1994; Wilson and Ruff, 1999)

  • Breeding interval
    Mexican woodrats will usually have two litters per breeding season.
  • Breeding season
    Breeding occurs from March through May and may last longer in the southern part of the range.
  • Range number of offspring
    2 to 5
  • Range gestation period
    31 to 34 days
  • Average gestation period
    33 days
  • Range weaning age
    4 to 6 weeks
  • Range age at sexual or reproductive maturity (female)
    2 (low) months
  • Average age at sexual or reproductive maturity (male)
    9 months

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)

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; "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)

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)

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

Predation

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)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Although it is not documented as a common ocurrance, Mexican woodrats may serve as food for humans. (Davis, 1960)

  • Positive Impacts
  • food

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)

  • Negative Impacts
  • injures humans
    • carries human disease

Conservation Status

This species does not have a conservation status because it is not threatened.

Contributors

Matthew Wund (editor), University of Michigan-Ann Arbor.

Jill Ceitlin (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

mycophage

an animal that mainly eats fungus

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

2004. "Natural Diversity Information Source" (On-line). Wildlife Mexican Woodrat Page. Accessed March 14, 2004 at http://ndis.nrel.colostate.edu/wildlifespx.asp?SpCode=050787.

1989. "Oklahoma Museum of Natural History Mammal Key" (On-line). Accessed March 12, 2004 at http://www.snomnh.ou.edu/mammalkey/Neotoma_mexicana.html.

2004. "Utah Division of Wildlife Resources" (On-line). Accessed March 14, 2004 at http://dwrcdc.nr.utah.gov/rsgis2/Search/Display.asp?FINm=neotmexi.

2003. "eNature" (On-line). Mexican Woodrat. Accessed March 15, 2004 at http://www.enature.com/fieldguide/showSpeciesRECNUM.asp?recnum=MA0413.

Coln, J. 1987. An unusual woorat nest. Texas Journal of Science, 39/2: 192-193.

Cornely, J., R. Baker. 1986. Neotoma mexicana. Mammalian Species, 262: 1-7.

Davis, W., D. Schmidly. 1997. "The Mammals of Texas" (On-line). Accessed March 12, 2004 at http://www.nsrl.ttu.edu/tmot1/neotmexi.htm.

Davis, W. 1960. Mammals of Texas. Austin: Game and Fish Commission.

Edwards, C., R. Bradley. 2001. Molecular systematics and historical phylobiogeography of the Neotoma mexicana species group. Journal of Mammalogy, 83/1: 20-30.

Findley, J., A. Harris, D. Wilson, C. Jones. 1975. Mammals of New Mexico. Albuquerque: University of New Mexico Press.

Fulhorst, C., R. Charrel, S. Weaver, T. Ksiazek, R. Bradley, M. Milazzo, R. Tesh, M. Bowen. 2001. Geographic distribution and genetic diversity of whitewater arroyo virus in the southwestern United States. Emerging Infectious Diseases, 7/3: 403-407.

Howe, R. 1978. Agonistic behavior of three sympatric species of wood rats, Neotoma mexicana, Neotoma albigula and Neotoma stephensi. Journal of Mammalogy, 59/4: 780-776.

Meaney, C., D. Armstrong. 1994. Mammals of Colorado. Denver: University Press of Colorado.

Norris, D., B. Johnson, J. Piesman, G. Maupin, J. Clark, W. Black. 1997. Culturing selects for specific genotypes of Borrelia burgdorferi in an enzootic cycle in Colorado. American Society for Microbiology, 35/9: 2359-2364.

Palmer, R. 1954. Mammal Guide of North America North of Mexico. Garden City, NY: Doubleday and Company, Inc..

Peterson, A., V. Sanchez-Cordero, B. Beard, J. Ramsey. 2002. Ecologic niche modeling and potential reservoirs for chagas disease, Mexico. Emerging Infectious Diseases, 8/7: 662-667.

Reid, F. 1997. Field Guide to the Mammals of Central America and South Eastern Mexico. New York: Oxford University Press.

Ward, J., J. Ganey. 2003. "Rocky Mountain Research Station" (On-line). Coordinated Management-monitoring and Research Program for the Rio Penasco Watershed Restoration Project. Accessed March 15, 2004 at http://www.rmrs.nau.edu/lab/4251/spowmon/research.html.

Wilson, D., S. Ruff. 1999. Smithsonian Book of North American Mammals. Washington: Smithsonian Institute Press.

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