Animal Diversity Web

Ge­o­graphic Range

South­ern plains woodrats (Neotoma mi­cro­pus) have a range that ex­tends north into south­east­ern Col­orado and south­west­ern Kansas and south through west­ern Ok­la­homa, west­ern Texas and north­east­ern Mex­ico. They also in­habit the ma­jor­ity of New Mex­ico ex­cept the far north­west­ern por­tion of the state. (Braun and Mares, 1989; Thies and Caire, 1991)

• Biogeographic Regions
• nearctic
  • native

Habi­tat

South­ern plains woodrats pre­fer dry grass­land en­vi­ron­ments, they favor cac­tus grass­lands but can also be found in shrubby or mesquite grass­lands, re­gard­less, they are typ­i­cally found in close prox­im­ity to shrubs or cacti. They are gen­er­ally found in semi-arid, flat plains and low val­leys, often lo­cated be­tween tim­ber­lands and deserts, they may also be found on rocky hill­sides. Most pop­u­la­tions con­struct below ground dens, how­ever, some pop­u­la­tions are pre­cluded from this be­hav­ior due to the soil qual­ity in their area. Where den ex­ca­va­tion is not pos­si­ble, south­ern plains woodrats use rock crevices and trees for cover. (Braun and Mares, 1989; Charles, et al., 2012; Reid, 2006; Suchecki, et al., 2004)

• Habitat Regions
• terrestrial

• Terrestrial Biomes
• desert or dune
• savanna or grassland
• scrub forest

Phys­i­cal De­scrip­tion

South­ern plains woodrats are medium-sized ro­dents with white feet, large ears, dark eyes and long whiskers. Their dor­sal side has soft, dense, gray­ish, some­times buffy fur, with oc­ca­sional black hairs on their back. Their ven­tral side is gray with a white throat and pec­toral re­gion. 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 dig­its on each foot. Their den­tal for­mula is 1/1, 0/0, 0/0, 3/3, with a total of 16 teeth. In­di­vid­u­als in coastal Texas and south-cen­tral Kansas tend to be larger than in­di­vid­u­als in other pop­u­la­tions. South­ern plains woodrats show no sex­ual di­mor­phism in col­oration. Al­though males tend to be some­what larger than fe­males, they show no sig­nif­i­cant sex­ual di­mor­phism in size. Adult an­i­mals molt each year, typ­i­cally be­tween June and Oc­to­ber. Ju­ve­niles go through 2 to 3 molts be­fore achiev­ing their adult pelage. (Braun and Mares, 1989)

• Other Physical Features
• endothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range mass

  180 to 317 g

  6.34 to 11.17 oz

• Average length

  355 to 370 mm

  in

Re­pro­duc­tion

The mat­ing be­hav­ior of south­ern plains woodrats is a long and de­tailed 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 con­tinue to cop­u­late every 2 to 10 min­utes, prior to each mat­ing at­tempt, the fe­male per­forms a dis­play. Cop­u­la­tion lasts from 2 to 90 sec­onds, but av­er­ages 10 to 20 sec­onds. Fe­males may be­come preg­nant with as lit­tle as 2 cop­u­la­tions, but they are much more re­pro­duc­tively suc­cess­ful with four or five cop­u­la­tions. Based on their home range dis­tri­b­u­tion, these an­i­mals are as­sumed to en­gage in a promis­cu­ous mat­ing sys­tem. (Braun and Mares, 1989; Con­ditt and Rib­ble, 1997; Suchecki, et al., 2004)

• Mating System
• polygynandrous (promiscuous)

South­ern plains woodrats typ­i­cally breed in the early spring and pro­duce 1 lit­ter per year. How­ever, south­ern pop­u­la­tions may pro­duce 2 or more lit­ters per year as a re­sult of 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 in­di­vid­u­als, each weigh­ing about 10 to 13 grams. Lit­ters are most fre­quently com­posed of 2 to 3 in­di­vid­u­als, al­though vari­a­tion can be seen in pop­u­la­tions, north­ern pop­u­la­tions have an av­er­age of 3 in­di­vid­u­als per lit­ter while south­ern pop­u­la­tions av­er­age 2. Males and fe­males grow at a sim­i­lar rate; how­ever, by about 6 months old, males are gen­er­ally some­what larger. Tech­ni­cally, sex­ual ma­tu­rity oc­curs at 10 weeks for males and 6 months for fe­males, how­ever, most in­di­vid­u­als do not mate im­me­di­ately after reach­ing ma­tu­rity. (Braun and Mares, 1989; Pitts, et al., 1985)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• Breeding interval

  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

There is cur­rently very lit­tle in­for­ma­tion avail­able re­gard­ing the parental be­hav­ior of south­ern plains woodrats. How­ever, an en­dan­gered mem­ber of the same genus, Key Largo woodrats (Neotoma flori­dana), have been stud­ied in the cap­tive en­vi­ron­ment. Sim­i­lar to south­ern plains woodrats, fe­male Key Largo woodrats typ­i­cally nurse and pro­tect their young for ap­prox­i­mately 30 days fol­low­ing par­tu­ri­tion. Young are fre­quently seen grasp­ing tightly to their mother's mam­mae, al­though suck­ling de­creases over the 30 day nurs­ing pe­riod. In the cap­tive en­vi­ron­ment, fe­male Key Largo woodrats were able to for­age with and with­out suck­ling young; how­ever, there is cur­rently no in­for­ma­tion avail­able re­gard­ing wild in­di­vid­u­als. Oc­ca­sion­ally, fe­males forcibly re­move the young from their mam­mae, al­though about 75% of the time they have at least one off­spring at­tached. Young do not choose to leave the mam­mae until they are about 13 to 21 days old; they begin eat­ing solid food around the same time. De­pen­dent off­spring are often ob­served lick­ing their mother's mouth, the causes of this be­hav­ior are un­known, but it may ei­ther pro­vide mois­ture or scent cues. No pa­ter­nal care is pro­vided in this genus. (Al­li­good, et al., 2008; Braun and Mares, 1989)

• Parental Investment
• female parental care

Lifes­pan/Longevity

South­ern plains woodrats have a fairly short lifes­pan. Fe­males tend to live longer, par­tic­u­larly among those that sur­vive until adult­hood. Due to high mor­tal­ity among im­ma­ture in­di­vid­u­als, males have an av­er­age lifes­pan of 5.6 months and fe­males have an av­er­age lifes­pan of 7.6 months. The av­er­age lifes­pan among in­di­vid­u­als that sur­vive to adult­hood is not known. 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

Be­hav­ior

South­ern plains woodrats are soli­tary and ter­ri­to­r­ial ex­cept when mat­ing. While some stud­ies have failed to ob­serve more than one adult woodrat in a nest at one time (Con­ditt and Rib­ble, 1997), oth­ers have ob­served an adult male and fe­male re­sid­ing in the same nest dur­ing the day­time (Suchecki et al. 2004). When no longer under ma­ter­nal care, 65% of males and 38% of fe­males dis­perse from their place of birth. Dens with 2 to 5 en­trances are built un­der­neath cacti or shrubs. Many in­di­vid­u­als use the same den for life, par­tic­u­larly among fe­males. When the soil is con­ducive, their un­der­ground dens are used for food stor­age, nest­ing and preda­tor eva­sion. Their nest cham­ber is full of soft grasses and is kept free of food scraps and feces. Above ground, their nests are made of plant ma­te­r­ial and human trash, which has given them the nick­name "pack­rat". Ag­gres­sive en­coun­ters may ensue when res­i­dents de­fend 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)

• Key Behaviors
• terricolous
• nocturnal
• motile
• solitary
• territorial

• Range territory size

  157.8 to 1,829.2 m^2

Home Range

Their home range sizes may vary based on the lo­ca­tion of the pop­u­la­tion, re­gard­less; males tend to have a much larger range size. In south­west­ern Texas, the av­er­age home range size ranged from 971.3 to 1,335.5 me­ters squared. How­ever, the min­i­mum re­quired range space for males was 232.4 m2, com­pared to 157.8 m2 for fe­males. Whereas the av­er­age range size in south­ern Texas was 1,696 to 1,829.2 m2 for males and 188 to 258.2 m2 for fe­males. Like­wise, the over­all home range size in Guadalupe Moun­tains Na­tional Park is 258 m2. Home ranges may over­lap; there are gen­er­ally 0 to 31 in­di­vid­u­als per hectare. Their daily move­ment is min­i­mal, stick­ing to their cac­tus patch or a neigh­bor­ing patch; they rarely cross areas with­out veg­e­ta­tion. South­ern plains woodrats may have paths lead­ing from their dens to many of their pre­ferred feed­ing areas. (Braun and Mares, 1989; Linzey, et al., 2008; Suchecki, et al., 2004)

Com­mu­ni­ca­tion and Per­cep­tion

Scent mark­ing is an im­por­tant method of com­mu­ni­ca­tion for woodrats. South­ern plains woodrats are able to iden­tify mem­bers of the op­po­site sex by scent. Males use urine and sebum to at­tract mates, while fe­males use their urine and feces. Like­wise, south­ern plains woodrats are ex­tremely sen­si­tive to sound. These an­i­mals quickly react to even the slight­est sound or move­ment. They pro­duce a drum­ming sound by hit­ting the ground with their hind feet; this may act as an alarm call or es­tab­lish ter­ri­tory. South­ern plains woodrats also have ex­tremely acute vi­sion, which may help them evade preda­tors. (Au­gust, 1978; Braun and Mares, 1989; Reid, 2006)

• Communication Channels
• acoustic
• chemical

• Other Communication Modes
• scent marks
• vibrations

• Perception Channels
• visual
• tactile
• acoustic
• vibrations
• chemical

Food Habits

Their diet con­sists of 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 ob­tain their re­quired water from the food they eat. Dur­ing droughts, they de­pend on cac­tus pulp for food and mois­ture. These an­i­mals des­ig­nate an area of their den for caching food. South­ern plains woodrats are larder hoard­ers and begin col­lect­ing food stores in late sum­mer and early au­tumn. Each year they typ­i­cally lose a great deal of weight dur­ing au­tumn and win­ter and gain weight dur­ing the win­ter and spring. Oc­ca­sion­ally, their caches are raided by other an­i­mals in­clud­ing Ord's kan­ga­roo rats and hispid pocket mice. (Braun and Mares, 1989; Reid, 2006)

• Primary Diet
• herbivore
  • folivore
  • lignivore

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

• Foraging Behavior
• stores or caches food

Pre­da­tion

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. How­ever, they may be im­mune to fairly large quan­ti­ties of snake venom. 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)

• Known Predators

  • white-tailed hawks (Buteo albicaudatus)
  • Harris's hawks (Parabuteo unicinctus)
  • great horned owls (Bubo viriginanus)
  • barn owls (Tyto alba)
  • greater roadrunners (Geococcyx californianus)
  • raccoons (Procyon lotor)
  • bobcats (Felis rufus)
  • coyotes (Canis latrans)
  • foxes (Vulpini)
  • western rat snakes (Elaphe obsolete)
  • western diamondback rattlesnakes (Crotalus atrix)
  • fire ants (Solenopsis)

Ecosys­tem Roles

South­ern plains woodrats serve as im­por­tant pri­mary con­sumers through­out their range, 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 an im­por­tant eco­log­i­cal en­gi­neer. The mi­cro­cli­mate cre­ated in their dens is es­sen­tial for crick­ets, wolf spi­ders and lycid bee­tle lar­vae, like­wise, 40 ad­di­tional in­ver­te­brate taxa also ca­su­ally use this habi­tat. Their dens are also by other ver­te­brate species as well in­clud­ing or­nate box tur­tles, side-blotch lizards, go­pher snakes, cac­tus mice and deer mice. Wood de­com­pos­ing fungi also re­side within their dens due to the high mois­ture con­tent. Their urine and feces, in ad­di­tion to the waste cre­ated by the other oc­cu­pants of their den, fer­til­ize the soils and cre­ate nu­tri­ent en­riched areas. (Braun and Mares, 1989; Charles, et al., 2012; Whit­ford and Stein­berger, 2010)

• Ecosystem Impact
• creates habitat

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Woodrats are some­times used as bi­o­log­i­cal in­di­ca­tors to de­tect changes in habi­tat qual­ity, par­tic­u­larly in Guadalupe Moun­tains Na­tional Park. Their pop­u­la­tion den­sity is in­versely re­lated to the qual­ity and quan­tity of the grass­land. (Braun and Mares, 1989; Charles, et al., 2012)

• Positive Impacts
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

South­ern plains woodrats are po­ten­tial vec­tors of a num­ber of zoonotic ill­nesses. They are reser­voir hosts of Leish­ma­nia mex­i­cana, which can be trans­mit­ted to hu­mans due to both species' in­ter­ac­tions with sand flies. These an­i­mals may also be vec­tors for tu­laremia, plague, q fever, re­laps­ing fever and Rocky Moun­tain spot­ted fever. South­ern plains woodrats 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)

• Negative Impacts
• injures humans
  • carries human disease
• causes or carries domestic animal disease

Con­ser­va­tion Sta­tus

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. Like­wise, they have no spe­cific list­ing by CITES. (Linzey, et al., 2008)

• IUCN Red List

  Least Concern

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

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.