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southern plains woodrat

Neotoma micropus

What do they look like?

Southern plains woodrats are medium-sized rodents with white feet, large ears, dark eyes and long whiskers. Their fur is dense, soft and grayish, or sometimes buffy, with occasional black hairs on their back. Their under belly is gray and they have a white throat. Their tail is dark above and lighter on the bottom side, it is also short, heavy and mostly hairless. Males have an average total body length of 370 mm, including an average tail length of 152.6 mm, whereas females have an average total body length of 355.8 mm, including an average tail length of 147.1 mm. They have four toes on each foot. They have a total of 16 teeth. Southern plains woodrats from coastal Texas and south-central Kansas may be larger than woodrats from other ranges. Males and females are the same color and males are slightly larger than females. Adult animals molt each year, usually between June and October. Juveniles go through 2 to 3 molts before they get their adult pelage. (Braun and Mares, 1989)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    180 to 317 g
    6.34 to 11.17 oz
  • Average length
    355 to 370 mm
    in

Where do they live?

Southern plains woodrats (Neotoma micropus) are found as far north as southeastern Colorado and southwestern Kansas and as far south as western Oklahoma, western Texas and northeastern Mexico. They also can also be found throughout New Mexico except the far northwestern corner of the state. (Braun and Mares, 1989; Thies and Caire, 1991)

What kind of habitat do they need?

Southern plains woodrats are usually found near shrubs and cacti in dry grasslands, such as cactus grasslands or shrubby and mesquite grasslands. These animals like semi-arid, flat plains and low valleys, usually found between timberlands and deserts, they may also be found on rocky hillsides. They usually dig below ground dens, although they are not able to in certain areas of their range due to the soil quality. Where they are not able to dig below ground dens, southern plains woodrats use rock crevices and trees for cover. (Braun and Mares, 1989; Charles, et al., 2012; Reid, 2006; Suchecki, et al., 2004)

  • These animals are found in the following types of habitat
  • terrestrial

How do they reproduce?

Southern plains woodrats have a very involved mating process. Males and females cautiously approach each other in a crouched position while partially flexing their legs. These animals then smell each other’s faces while touching their whiskers together, after which, they stand on their hind feet and touch their forefeet together while chattering their teeth. Individuals then bob their heads side to side and forward and back. The female quickly passes back and forth in front of the male in a crouched position, making short hops and rapidly drumming her hind feet. She then drags her back end on the ground, directing it toward the male while giving low-pitched raspy squeaks. The male approaches from the rear and mounts. The pair may mate every 2 to 10 minutes for 2 to 90 seconds at a time. Based on male and female home ranges, they probably have a promiscuous mating system. (Braun and Mares, 1989; Conditt and Ribble, 1997; Suchecki, et al., 2004)

Southern plains woodrats typically breed in the early spring and have 1 litter per year. However, animals found further south may produce 2 or more litters per year due to their continuous breeding season, which peaks in early spring and late fall. Their gestation period lasts about 33 to 35 days, after which, they have litters of 1 to 4 pups, each weighing about 10 to 13 grams. Males and females grow at the same rate, however, males are usually somewhat larger by the time they are 6 months old. (Braun and Mares, 1989; Pitts, et al., 1985)

  • How often does reproduction occur?
    Southern plains woodrats mate frequently during the breeding season.
  • Breeding season
    Most populations breed in the early spring, however, southern populations may have a continuous breeding season.
  • Range number of offspring
    1 to 4
  • Range gestation period
    33 to 35 days
  • Average weaning age
    30 days
  • Average time to independence
    30 days
  • Average age at sexual or reproductive maturity (female)
    6 months
  • Average age at sexual or reproductive maturity (male)
    10 weeks

Very little I known about the parental behavior of southern plains woodrats specifically, however, their close relatives, Key Largo woodrats (Neotoma floridana), have been studied in zoos. Similar to southern plains woodrats, female Key Largo woodrats nurse and protect their young for about 30 days after birth. Young grasp tightly to their mother's teats, although the amount of time they spend suckling decreases over the 30 day nursing period. In zoos, female Key Largo woodrats were able to forage for food with and without suckling young; however, it is not known whether they can also do this in the wild. Occasionally, females remove the young from their teats, although they have at least one offspring attached about 75% of the time. Young do not choose to leave the teats until they are about 13 to 21 days old; they begin eating solid food around the same time. Pups often lick their mother's mouth, this might help them get moisture or scent cues. Males do not give any parental care. (Alligood, et al., 2008; Braun and Mares, 1989)

How long do they live?

Southern plains woodrats have short lives. Many of them do not survive until adulthood, because of that the average lifespan for males is 5.6 months and the average lifespan for females is 7.6 months. Among the individuals that do survive until adulthood, females tend to live longer. The oldest known individual survived to be about 2.25 years old. (Braun and Mares, 1989)

  • Range lifespan
    Status: wild
    27 (high) months
  • Average lifespan
    Status: wild
    5.6 to 7.6 months

How do they behave?

Southern plains woodrats are solitary and territorial. These animals usually stay in their nests alone except for females with young. Southern plains woodrats build dens underneath cacti or shrub with 2 to 5 entrances. Many of them use the same den for life, particularly females. They also dig underground tunnels that they use for food storage, nesting and escaping predators. They keep their nest chamber clean and full of soft grasses. Their above ground nest is made of plant material and human trash, which has given them the nickname "packrat". They can be aggressive to other animals while defending their territory. Southern plains woodrats are nocturnal and are most active between dusk and midnight. (Braun and Mares, 1989; Conditt and Ribble, 1997; Reid, 2006; Suchecki, et al., 2004)

  • Range territory size
    157.8 to 1,829.2 m^2

Home Range

Male southern plains woodrats tend to have a much larger range size than females. In southwestern Texas, the minimum required range space for males was 232.4 meters squared, compared to 157.8 meters squared for females. The average home range size in southern Texas is 1,696 to 1,829.2 meters squared for males and 188 to 258.2 meters squared for females. Their home ranges sometimes overlap and there are generally 0 to 31 individuals per hectare. They do not move very far every day, they generally stick to their cactus patch or a neighboring patch. They use paths leading from their dens to their preferred feeding areas. (Braun and Mares, 1989; Linzey, et al., 2008; Suchecki, et al., 2004)

How do they communicate with each other?

Southern plains woodrats often scent mark for communication. These animals are able to identify members of the opposite sex by scent. They are also very sensitive to sound, they react quickly to even the slightest sound or movement. Southern plains woodrats make a drumming sound by hitting the ground with their hind feet, they may use this as an alarm or territory call. They also have very good vision, which may help them avoid predators. (August, 1978; Braun and Mares, 1989; Reid, 2006)

What do they eat?

They eat cactus leaves, cactus fruits, berries, mesquite pods and beans, acorns and other types of plant material. Some of their favorite food items include the joints, fruits, leaf blades and seeds of prickly pears (Opuntia) and Great Plains yuccas (Yucca glauca). They get the moisture they need from the food they eat. These animals use an area of their den for storing, or caching food. Southern plains woodrats hoard food for the winter; they begin collecting food in late summer and early autumn. Their caches are sometimes raided by other animals including Ord's kangaroo rats and hispid pocket mice. (Braun and Mares, 1989; Reid, 2006)

  • Plant Foods
  • leaves
  • roots and tubers
  • seeds, grains, and nuts
  • fruit

What eats them and how do they avoid being eaten?

Southern plains woodrats are preyed upon by many different animals. They are hunted by a variety of birds such as white-tailed hawks, Harris's hawks, great horned owls, barn owls and greater roadrunners, as well as a variety of mammal species including raccoons, bobcats, coyotes and foxes. Southern plains woodrats are also hunted by western rat snakes and western diamondback rattlesnakes, particularly in the southern part of their range. Fire ants are also known to trap and kill adults and nestlings. To avoid predation, southern plains woodrats often hide in their dens. (Braun and Mares, 1989; Suchecki, et al., 2004)

What roles do they have in the ecosystem?

Southern plains woodrats are considered primary consumers, consuming nuts, berries, leaves and many other types of vegetation. They also host many different species of parasites such as fleas, ticks, mites, lice, nematodes and protozoa. This species is considered an ecological engineer due to the habitat they create by making nests and digging dens. The microclimate created by their dens is essential for crickets, wolf spiders and lycid beetle larvae. There are also 40 other invertebrate groups that casually use this habitat. Their dens are used by other vertebrate species as well including ornate box turtles, side-blotch lizards, gopher snakes, cactus mice and deer mice. Their urine and feces, in addition to the waste created by the other animals living in their dens, fertilize the soils and create nutrient enriched areas. (Braun and Mares, 1989; Charles, et al., 2012; Whitford and Steinberger, 2010)

  • Ecosystem Impact
  • creates habitat
Commensal or parasitic species (or larger taxonomic groups) that use this species as a host

Do they cause problems?

Southern plains woodrats carry human diseases such as tularemia, plague, q fever, relapsing fever and Rocky Mountain spotted fever. They may also help spread chagas disease by hosting Trypanosoma cruzi, which infects both humans and other animals. (Charles, et al., 2012; Clarke, et al., 2013)

How do they interact with us?

Woodrats are sometimes considered biological indicators; they are used for monitoring changes in habitat quality in Guadalupe Mountains National Park. (Braun and Mares, 1989; Charles, et al., 2012)

  • Ways that people benefit from these animals:
  • research and education

Are they endangered?

This species is currently not considered endangered or threatened. According to the IUCN, southern plains woodrats have a stable population with a status of 'least concern' due to their wide distribution and large population size. (Linzey, et al., 2008)

Contributors

Demetri Lafkas (author), Northern Michigan University, Leila Siciliano Martina (author, editor), Animal Diversity Web Staff, John Bruggink (editor), Northern Michigan University.

References

Alligood, C., C. Wheaton, H. Forde, K. Smith, A. Daneault, R. Carlson, A. Savage. 2008. Pup development and maternal behavior in captive Key Largo woodrats (Neotoma floridana smalli). Zoo Biology, 27-5: 394-405.

August, P. 1978. Scent Communication in the Southern Plains Wood Rat, Neotoma micropus. American Midland Naturalist, 99/1: 206-218.

Braun, J., M. Mares. 1989. Neotoma micropus. Mammalian Species, 330: 1-9.

Charles, R., S. Kjos, A. Ellis, J. Dubey, B. Shock, M. Yabsley. 2012. Parasites and vector-borne pathogens of southern plains woodrats (Neotoma micropus) from southern Texas. Parasitology Research, 110: 1855-1862.

Clarke, C., K. Bradley, J. Wright, J. Glowicz. 2013. Case report: Emergence of autochthonous cutaneous Leishmaniasis in northeastern Texas and southeastern Oklahoma. American Journal of Tropical Medicine and Hygiene, 88-1: 157-161.

Conditt, S., D. Ribble. 1997. Social Organization of Neotoma micropus, the Southern Plains Woodrat. American Midland Naturalist, 137/2: 290-297.

Linzey, A., R. Timm, S. Alvarez-Castaneda, I. Castro-Arellano, T. Lacher. 2008. "Neotoma micropus" (On-line). IUCN Redlist of Threatened Species. Accessed August 29, 2013 at www.iucnredlist.org.

Pitts, R., J. Sharninghausen, H. Garner. 1985. A Note on the Extension of the Breeding Seasons of the Southern Plains Woodrat (Neotoma micropus Baird) and the Plains Pocket Gopher (Geomys bursarius Shaw) in Southcentral Texas. Bios, 56/2: 89-90.

Reid, F. 2006. Mammals of North America. Singapore: Houghton Mifflin Company.

Suchecki, J., D. Ruthven, C. Fulhorst, R. Bradley. 2004. Natural history of the southern plains woodrat Neotoma micropus (Rodentia: Muridae) from southern Texas. Texas Journal of Science, 56-2: 131-140.

Thies, M., W. Caire. 1991. Nearest-Neighbor Analysis of the Spatial Distribution of Houses of Neotoma micropus in Southwestern Oklahoma. The Southwestern Naturalist, 36/2: 233-237.

Whitford, W., Y. Steinberger. 2010. Pack rats (Neotoma spp.): Keystone ecological engineers?. Journal of Arid Environments, 74: 1450-1455.

 
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Lafkas, D. and L. Siciliano Martina 2013. "Neotoma micropus" (On-line), Animal Diversity Web. Accessed July 21, 2019 at http://www.biokids.umich.edu/accounts/Neotoma_micropus/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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