White-Throated Woodrat
Encyclopedia
The white-throated woodrat (Neotoma albigula) is a species of rodent
in the family Cricetidae
. It is found from central Mexico
north to Utah
and Colorado
in the United States
. It is primarily a western species in the United States, extending from central Texas
west to southeastern California
. Since that work, populations east of the Rio Grande
in New Mexico
and Trans-Pecos Texas have been assigned to the white-toothed woodrat (Neotoma leucodon).
The animal lives mostly in the Upper and Lower Sonoran life zone
s, occurring from Pinyon-juniper woodland
in higher country to desert
habitats at lower elevations.
As with other species of woodrats, the white-throated woodrat constructs middens of a variety of materials such as sticks, cactus parts, and miscellaneous debris. An above-ground chamber within the midden contains a nest lined with grasses and kept free of feces. In non-rocky areas, the den usually is several feet in diameter and most commonly built around the base of a shrub that gives additional cover. In areas of rocky outcrops, crevices often are utilized, with sticks and other materials preventing free access to the nesting chamber.
Molecular data suggest that this species separated from other species of the Neotoma floridana group (Neotoma floridana, Neotoma micropus, Neotoma leucodon) about 155,000 years ago during the Illinoian Stage
of the Pleistocene
. This fits nicely with the oldest known fossils from Slaton, Texas
. This rodent is a common fossil in Southwestern cave faunas, with over 20 fossil localities of Pleistocene age known from New Mexico alone.
In general, white-throated woodrats occupy desert grassland
s, semiarid shrubland
s, saguaro (Carnegiea gigantea) cactus communities, pinyon-juniper (Pinus-Juniperus spp.) woodlands, interior ponderosa pine (P. ponderosa var. scopulorum) forests, and Madrean evergreen woodland (Pinus spp.-Quercus spp.).
White-throated woodrats prefer habitat with low tree canopy cover, high shrub and rock cover, and coarse woody debris
. When available, natural and human constructed riparian habitat may be used by white-throated woodrats.
-Gambel oak
habitat in the Hualapai Mountains in Arizona, white-throated woodrat presence was negatively associated with high tree cover and high herbaceous cover and positively associated with high shrub and rock cover. On plots where white-throated woodrats were trapped, mean tree canopy cover ranged from 30% to 57%, mean herbaceous cover ranged from 2% to 10%, mean shrub cover ranged from 5% to 19%, and mean rock cover ranged from 3% to 14%.
In desert riparian floodplain habitat at Montezuma Castle National Monument, Arizona, white-throated woodrats were more abundant in an active riparian channel and floodplain that had lower tree cover and a higher percentage of forbs and rocks than a mesquite bosque. The active riparian channel and floodplain was dominated by desert willow, velvet ash (Fraxinus velutina), Arizona sycamore (Platanus wrightii), and velvet mesquite. The mesquite bosque was dominated by velvet mesquite, catclaw acacia, and broom snakeweed.
In pinyon-juniper woodlands in Grant County, New Mexico
, total overstory density was more important than overstory species composition in influencing white-throated woodrat occurrence. The greatest densities of white-throated woodrat houses were on plots containing 376 to 750 overstory plants per hectare :
White-throated woodrats prefer rocky areas within forested habitat, including ledges, slides, cliffs, and canyons. In a ponderosa pine forest on the Beaver Creek Watershed in the Coconino National Forest, all white-throated woodrats were captured within 210 feet (64 m) of rocky habitat. In ponderosa pine-Gambel oak habitat in the Hualapai Mountains, white-throated woodrat presence was positively associated with high (3% to 19%) rock cover.
Although preferred habitat differed between male and female white-throated woodrats on the Santa Rita Experimental Range, Arizona, both genders showed some preference for riparian woodland typified by Arizona white oak and netleaf hackberry :
thickets that grew closest to a human constructed water development. White-throated woodrats were trapped least often in habitat dominated by creosotebush and furthest away (distance not given) from the water development. No white-throated woodrats were trapped at a nearby dry water development.
White-throated woodrats also occupied a human constructed desert riparian habitat at No Name Lake on the Colorado River Indian Reservation on the Arizona side of the Colorado River
. The area was cleared of nonnative tamarisk (Tamarix spp.) and 80% of the area was planted with native Fremont cottonwood and honey mesquite. Other vegetation included Goodding's willow Salix gooddingii
, blue paloverde (Parkinsonia florida
), big saltbush (Atriplex lentiformis
), and California fan palm (Washingtonia filifera
).
is preferred by white-throated woodrats for cover (see Cover). In pinyon-juniper woodlands at the Piñon Canyon Maneuver site near Trinidad, Colorado
, white-throated woodrats were captured most often in areas with coarse woody debris. In an actively flooded riparian channel and floodplain at Montezuma Castle National Monument, white-throated woodrat occurrence was significantly (P<0.05) greater in areas containing coarse woody debris than areas without coarse woody debris.
In a pinyon-juniper woodland in the Gila National Forest, New Mexico, white-throated woodrats responded favorably to mechanical treatments that increased the amount of coarse woody debris. Of 4 treatments (untreated; bulldozed/piled/burned; bulldozed; and thinned), white-throated woodrats were most abundant on bulldozed plots and thinned plots, where slash accumulations were 2.5 to 3 times greater than on other plots. On bulldozed plots, Colorado pinyon, one-seed juniper, and alligator juniper trees were pushed over and left in place. On thinned plots, Colorado pinyon and juniper were cut to a minimum spacing of 20.0 feet (6.1 m) and left in place. The table below shows total numbers of woodrats on 4 plots :
White-throated woodrat density increased in a pinyon-juniper woodland in Grant County, New Mexico, where trees were uprooted and piled to improve livestock grazing. The felled trees provided white-throated woodrats with cover and building materials.
Houses are built by white-throated woodrats at the base of trees, shrubs, and cacti or in piles of coarse woody debris. White-throated woodrats prefer to construct houses at the bases of plants that provide both adequate shelter and food. Houses are constructed of various materials and are typically 3 to 10 feet (1–3 m) in diameter and up to 3 feet tall. Dens function as houses but are located in rock crevices, rock fissures, and under boulder piles.
Houses and dens enclose a system of runways and chambers, including the white-throated woodrat's nest. The nest averages 8 inches (20 cm) in diameter and is composed of soft, fine material including grass, shredded prickly-pear fibers, or juniper bark.
Building materials are gathered near the white-throated woodrat's shelter. At McDowell Mountain Regional Park, Arizona, white-throated woodrats gathered 30% of house building materials within 33 feet (10 m) from their shelter. Houses and dens are altered and refurbished during the year using new and old building materials.
In Guadalupe Mountains National Park and the Lower Sonoran zone of Arizona, use of building materials depended on availability. Juniper leaves and berries were used most often in a pinyon-juniper woodland, and mesquite leaves and pods and Christmas cactus (Cylindropuntia leptocaulis
) joints were used most often in a desert scrub habitat. In the Lower Sonoran desert of Arizona, white-throated woodrats favored some plants because of their structural and food values and favored other plants due to their availability. When available, cholla was used most often for building material due to its structural and food values. Mesquite sticks were used frequently. Although mesquite was seldom used for food, mesquite sticks were abundant at the base of plants so they were readily available. White bursage (Ambrosia dumosa) was very abundant and used for building material, even though plants were too small to shelter a white-throated woodrat den.
White-throated woodrats construct houses at the base of live and dead fallen juniper trees in pinyon-juniper woodlands in Arizona, New Mexico, Utah, and Texas. The base of pinyons are occasionally used.
Mesquite is often favored by white-throated woodrats for shelter in habitat dominated by mesquite in New Mexico, Arizona, California, and Texas. In habitat dominated by mesquite and creosote bush
in San Diego County, California
, all white-throated woodrat houses were located at the bases of honey mesquite
. Twenty to 26-foot tall (6–8 m) honey mesquite were preferred over 3 to 10 foot (1–3 m) tall honey mesquite, probably because they provided more shelter and abundant, accessible food. An exception in habitat dominated by mesquite occurred on the Santa Cruz river bottom near Tucson, Arizona, where white-throated woodrat houses were also built under netleaf hackberry, American black elderberry (Sambucus nigra
), skunkbush sumac (Rhus trilobata
), bear grass (Nolina
spp.), or saguaro
.
In habitats where yucca are abundant white-throated woodrats use the base of yucca for shelter sites. On the Jornada Experiment Range in New Mexico, and the Black Gap Wildlife Management Refuge in Trans-Pecos Texas , white-throated woodrats built houses at the bases and fallen trunks of yucca. Soaptree yucca
was used by white-throated woodrats in the lower Sonoran zone of the Lordsburg Plains in New Mexico and the San Simon Valley in Arizona.
Cholla and prickly-pear are often used by white-throated woodrats for cover because they provide excellent protection from predators, as well as food and water. One of the factors in white-throated woodrat shelter-site selection in McDowell Mountain Regional Park was presence of teddy bear cholla. In the Cholla Garden in Joshua Tree National Park
, white-throated woodrats depended on stands of jumping cholla (Cylindropuntia fulgida) for cover, and in the Lower Sonoran zone of Arizona, most white-throated woodrat dens were found at the bases of cholla and prickly-pear.
In Guadalupe Mountains National Park
, white-throated woodrat distribution may be limited more by the presence of Mexican woodrats (N. mexicana) and the southern plains woodrat (N. micropus) than by habitat limitations. In areas not inhabited by Mexican woodrats and southern plains woodrats, the white-throated woodrat constructed houses at bases of prickly-pears. In areas where white-throated woodrats and southern plains woodrats lived in close proximity, white-throated woodrat constructed houses under honey mesquite.
In the Lower Sonoran zone of Arizona and New Mexico, white-throated woodrats commonly used the bases of catclaw acacia for shelter.
White-throated woodrats selected multiple-stemmed plants over single-stemmed plants and a dense, low canopy over a tall, thin canopy in habitat dominated by triangle bursage in Organ Pipe Cactus National Monument
in Arizona and New Mexico
. White-throated woodrats selected house sites in reverse order of plant abundance: yellow paloverde 18.1 plants/ha, 6 houses; desert ironwood, 7.6 plants/ha, 14 houses; and organ pipe cactus, 5.0 plants/ha, 21 houses. Yellow paloverde was probably selected for shelter least often because it is a single-stemmed tree with a tall canopy; organpipe cactus (Stenocereus thurberi) was probably selected most often because it is a multiple-stemmed plant with many cylindrical stems branching near the ground from a central trunk, providing more cover.
White-throated woodrats occasionally use river banks, subterranean areas, or caves for shelter. In habitat dominated by honey mesquite and creosotebush at Carrizo Creek in San Diego County, white-throated woodrats sought cover either in river banks or subterranean burrows that were probably excavated by kangaroo rats (Dipodomys spp.). Lack of stick houses may have been due to a harsh summer climate, ease of burrowing in loose sand, scarcity of building materials, or adequate overhead protection by honey mesquite. River banks were 6 to 15 feet (2–5 m) high, and burrows were excavated at various heights from the bottom. Hole diameter was 3.5 to 7 inches (8.9–18 cm). White-throated woodrats also dwelled in subterranean burrows with as many as 8 openings, covered with a few small twigs, at the bases of honey mesquite. In a similar habitat type in the Mesilla Valley of New Mexico, white-throated woodrats denned in sand dunes created by banner-tailed kangaroo rats (D. spectabilis) around honey mesquite.
The mating season of white-throated woodrats varies across their range. In Arizona, the mating season is from January to August. In Big Bend National Park, Texas, mating occurs at least from January to November and may occur year-round. In California, the mating season is in February and March, according to Rainey, and in March, April, and possibly May, according to Schwartz and Bleich. The mating system of the white-throated woodrat is polygynous.
Gestation for white-throated woodrats lasts 37 to 38 days, and young are most often born in spring and early summer. In Arizona, mean litter sizes were 1.95 young/litter (n=93 litters) and 2.5 young/litter (n=27 litters).
Young white-throated woodrats are weaned 62 to 72 days after birth and reach sexual maturity 166 to 176 days after birth. Weaning and sexual maturity of the subspecies Neotoma albigula venusta in western Arizona, Sonora, and Baja California occur earlier: young are weaned between 27 and 40 days, and reach sexual maturity 80 to 87 days after birth. In Joshua Tree National Monument, California, young white-throated woodrats establish their own dens by August and September, several months after birth.
Descriptions of the home home range of the white-throated woodrat are lacking. The home range of 1 immature female white-throated woodrat on the Coconino National Forest, Arizona, was 47,760 ft² (4,437 m²).
White-throated woodrat density may be governed by the number of suitable plants available for shelter, food, and water. In Joshua Tree National Monument, there was a significant (P<0.001) positive relationship between white-throated woodrat density and teddybear cholla density, which provided shelter, food, and water. In the Mesilla Valley of southern New Mexico, white-throated woodrat density was more dependent on plants that provided sufficient water and food than on plants that provided shelter.
Foods eaten by white-throated woodrats depend on availability. In Great Basin
scrub desert and juniper woodlands in northern Arizona (Coconino County
) white-throated woodrat diet was 29% yucca, 24% juniper, 7% rabbitbrush (Chrysothamnus spp.), 6% sumac, 5% Apache-plume (Fallugia spp.), 4% sagebrush (Artemisia spp.), 4% saltbush, and 3% ephedra (Ephedra spp.). In the Lower Sonoran zone of southern Arizona (Santa Rita Experimental Range), cacti and mesquite were the primary foods eaten. For a complete list of foods eaten by white-throated woodrats in the Santa Rita Experimental Range, see Vorhies and Taylor. In the southern Great Basin, Navajo yucca (Y. baileyi) is an important food for the white-throated woodrat.
White-throated woodrats require large amounts of water obtained through various xerophytic plants, especially cacti. In Organ Pipe National Monument, white-throated woodrats relied heavily on teddybear cholla, buckhorn cholla (Cylindropuntia acanthocarpa), jumping cholla, and goatnut (Simmondsia spp.) for water. In Coconino County, white-throated woodrats obtained water from evergreen species (Ephedra spp., Yucca spp., and Juniperus spp.), which maintained a high year-round water content.
The white-throated woodrat diet varies seasonally. In Coconino County, white-throated woodrats ate a variety of plants, including deciduous shrubs, during warm, wet months when plant moisture was high. During cool, dry months, their diet was restricted largely to evergreen plants. Regardless of season, white-throated woodrats preferred to eat evergreen species. At Carrizo Creek, honey mesquite leaves, flowers, and fruits were the main foods eaten from the end of March until the end of summer. After honey mesquite lost its leaves, white-throated woodrats subsisted on stored beans, bark, and stems.
Some white-throated woodrats store food in their houses. Of 30 white-throated woodrat dens found in Doña Ana County, New Mexico
, 77% contained stored food. The average weight of stored food was 2.2 pounds (1.0 kg)/den, range 0.1 to 9.3 pounds (0.05–4.2 kg)/den). Most stored food consisted of mesquite beans and cacti and forb seeds. In general, white-throated woodrats collect food within a 98- to 164-foot (30–50 m) radius of their dens.
s (Lynx rufus), Ring-tailed Cat
s (Bassariscus astutus), coyotes (Canis latrans), American Badger
s (Taxidea taxus), Mexican spotted owls (Strix occidentalis lucida), Great Horned Owl
s (Bubo virginianus), bullsnake
s (Pituophis catenifer sayi), and rattlesnake
s (Crotalus spp.).
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
in the family Cricetidae
Cricetidae
The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, and New World rats and mice...
. It is found from central Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
north to Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
and Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It is primarily a western species in the United States, extending from central Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
west to southeastern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. Since that work, populations east of the Rio Grande
Rio Grande
The Rio Grande is a river that flows from southwestern Colorado in the United States to the Gulf of Mexico. Along the way it forms part of the Mexico – United States border. Its length varies as its course changes...
in New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
and Trans-Pecos Texas have been assigned to the white-toothed woodrat (Neotoma leucodon).
The animal lives mostly in the Upper and Lower Sonoran life zone
Life zone
The Life Zone concept was developed by C. Hart Merriam in 1889 as a means of describing areas with similar plant and animal communities. Merriam observed that the changes in these communities with an increase in latitude at a constant elevation are similar to the changes seen with an increase in...
s, occurring from Pinyon-juniper woodland
Pinyon-juniper woodland
A Pinyon-juniper woodland is a forest type characteristic of many parts the Western United States, often in higher elevations of desert ecoregions.-Locations:...
in higher country to desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
habitats at lower elevations.
As with other species of woodrats, the white-throated woodrat constructs middens of a variety of materials such as sticks, cactus parts, and miscellaneous debris. An above-ground chamber within the midden contains a nest lined with grasses and kept free of feces. In non-rocky areas, the den usually is several feet in diameter and most commonly built around the base of a shrub that gives additional cover. In areas of rocky outcrops, crevices often are utilized, with sticks and other materials preventing free access to the nesting chamber.
Molecular data suggest that this species separated from other species of the Neotoma floridana group (Neotoma floridana, Neotoma micropus, Neotoma leucodon) about 155,000 years ago during the Illinoian Stage
Illinoian Stage
The Illinoian Stage is the name used by Quaternary geologists in North America to designate the period of geologic time of ~300,000—130,000 years ago, a period of ~ during the middle Pleistocene when sediments comprising the Illinoian Glacial Lobe were deposited. It precedes the Sangamonian stage...
of the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
. This fits nicely with the oldest known fossils from Slaton, Texas
Slaton, Texas
Slaton is a city in Lubbock County, Texas, United States. The population was 6,109 at the 2000 census. It is part of the Lubbock Metropolitan Statistical Area.Slaton is named for Lubbock rancher and banker O.L. Slaton, Sr...
. This rodent is a common fossil in Southwestern cave faunas, with over 20 fossil localities of Pleistocene age known from New Mexico alone.
Disitribution
The ranges of the white-throated woodrat and its subspecies are from the southeastern corners of Nevada and California across southern Utah and all of Arizona to southwestern Colorado, across west Texas and south to central Mexico.- Neotoma albigula albigula (Hartley) – Northern New Mexico and northeastern Arizona south along the east side of the Sierra Madre Oriental, to southern Coahuila, Mexico. Also central Texas to western Arizona, and south along the western side of the Sierra Madre Occidental to central Sonora
- Neotoma albigula brevicauda (Durrant) – Utah and Colorado
- Neotoma albigula durangae (J. A. Allen) – Southwestern Chihuahua and central Durango, Mexico
- Neotoma albigula laplataensis (F.W. Miller) – Utah, Colorado, and Arizona
- Neotoma albigula latifrons (Merriam) – Michoacán, Mexico
- Neotoma albigula leucodon (Merriam) – East of the Rio Grande in New Mexico, Texas, and Oklahoma; Durango, Zacatecas, San Luis Potosí, Guanajuato, Jalisco, Aguascalientes, Querétaro, Hidalgo, and southeastern Coahuila, Mexico
- Neotoma albigula mearnsi (Goldman) – Arizona
- Neotoma albigula melanura (Merriam) – Central Sonora, Chihuahua, and Sinaloa, Mexico
- Neotoma albigula melas (Dice) – New Mexico
- Neotoma albigula robusta (Blair) – Texas
- Neotoma albigula seri (Townsend) – Northeastern Sonora, Mexico
- Neotoma albigula sheldoni (Goldman) – Northeastern Sonora, Mexico
- Neotoma albigula subsolana (Alvarez) – Coahuila, Tamaulipas, Nuevo León, and Coahuila, Mexico
- Neotoma albigula venusta (True) – Colorado River valley in western Arizona south to Sonora and Baja California, Mexico
- Neotoma albigula warreni – Colorado, Oklahoma, northeastern New Mexico, and Texas
In general, white-throated woodrats occupy desert grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s, semiarid shrubland
Shrubland
Shrubland, scrubland, scrub or brush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity...
s, saguaro (Carnegiea gigantea) cactus communities, pinyon-juniper (Pinus-Juniperus spp.) woodlands, interior ponderosa pine (P. ponderosa var. scopulorum) forests, and Madrean evergreen woodland (Pinus spp.-Quercus spp.).
Preferred habitat
The white-throated woodrat occupies a variety of plant communities from sea level to 9,200 feet (2,800 m) but is most common in Sonoran and Chihuahuan desert grassland and desert shrub habitats. The white-throated woodrat is generally associated with creosotebush, mesquite, cacti (particularly prickly-pear and cholla (Cylindropuntia spp.)), catclaw acacia, and paloverde. These plants provide cover and succulent plant food (>50% water by weight) (see section "Food habit"s), the 2 most critical habitat requirements for white-throated woodrat.White-throated woodrats prefer habitat with low tree canopy cover, high shrub and rock cover, and coarse woody debris
Coarse woody debris
Coarse woody debris is a term used in English-speaking countries for fallen dead trees and the remains of large branches on the ground in forests. Some prefer the term coarse woody habitat . A dead standing tree is known as a snag and provides many of the same functions as coarse woody debris...
. When available, natural and human constructed riparian habitat may be used by white-throated woodrats.
Tree, shrub, and rock cover
In several studies in Arizona, white-throated woodrats preferred low tree cover and high shrub, rock, and litter cover. In Ponderosa pinePonderosa Pine
Pinus ponderosa, commonly known as the Ponderosa Pine, Bull Pine, Blackjack Pine, or Western Yellow Pine, is a widespread and variable pine native to western North America. It was first described by David Douglas in 1826, from eastern Washington near present-day Spokane...
-Gambel oak
Gambel oak
Quercus gambelii, or Gambel oak, is a deciduous small tree or large shrub widespread in the foothills and lower mountain elevations of the central southwestern United States and northwestern Mexico: its range is centered on the Colorado Plateau–Four Corners states of Utah-Colorado,...
habitat in the Hualapai Mountains in Arizona, white-throated woodrat presence was negatively associated with high tree cover and high herbaceous cover and positively associated with high shrub and rock cover. On plots where white-throated woodrats were trapped, mean tree canopy cover ranged from 30% to 57%, mean herbaceous cover ranged from 2% to 10%, mean shrub cover ranged from 5% to 19%, and mean rock cover ranged from 3% to 14%.
In desert riparian floodplain habitat at Montezuma Castle National Monument, Arizona, white-throated woodrats were more abundant in an active riparian channel and floodplain that had lower tree cover and a higher percentage of forbs and rocks than a mesquite bosque. The active riparian channel and floodplain was dominated by desert willow, velvet ash (Fraxinus velutina), Arizona sycamore (Platanus wrightii), and velvet mesquite. The mesquite bosque was dominated by velvet mesquite, catclaw acacia, and broom snakeweed.
In pinyon-juniper woodlands in Grant County, New Mexico
Grant County, New Mexico
-2010:Whereas according to the 2010 U.S. Census Bureau:*84.9% White*0.9% Black*1.4% Native American*0.4% Asian*0.1% Native Hawaiian or Pacific Islander*2.8% Two or more races*9.8% Other races*48.3% Hispanic or Latino -2000:...
, total overstory density was more important than overstory species composition in influencing white-throated woodrat occurrence. The greatest densities of white-throated woodrat houses were on plots containing 376 to 750 overstory plants per hectare :
White-throated woodrats prefer rocky areas within forested habitat, including ledges, slides, cliffs, and canyons. In a ponderosa pine forest on the Beaver Creek Watershed in the Coconino National Forest, all white-throated woodrats were captured within 210 feet (64 m) of rocky habitat. In ponderosa pine-Gambel oak habitat in the Hualapai Mountains, white-throated woodrat presence was positively associated with high (3% to 19%) rock cover.
Riparian
The white-throated woodrat is well adapted to xeric habitats but may use natural and human constructed riparian areas when available.Natural
At Montezuma Castle National Monument, white-throated woodrat abundance was generally greater in an active riparian channel and floodplain than a mesquite bosque that was 7 to 13 feet (2–4 m) above the channel and floodplain and not subject to flooding. The active riparian channel and floodplain was dominated by desert willow, velvet ash, Arizona sycamore, and velvet mesquite. The mesquite bosque was dominated by velvet mesquite, catclaw acacia, and broom snakeweed. Despite greater abundance of white-throated woodrat in the active riparian channel and floodplain, body weights of male white-throated woodrat were significantly (P<0.05) higher in the mesquite bosque, suggesting that it was "higher quality" habitat.Although preferred habitat differed between male and female white-throated woodrats on the Santa Rita Experimental Range, Arizona, both genders showed some preference for riparian woodland typified by Arizona white oak and netleaf hackberry :
Human constructed
Construction of water developments in xeric habitat in Arizona may provide habitat and water for white-throated woodrats. On the Cabeza Prieta National Wildlife Refuge in southwestern Arizona, white-throated woodrats were trapped most often in velvet Mesquite BosqueMesquite Bosque
Mesquite Bosque is a vegetative association within the Southwestern United States, under the Kuchler scheme of plant association categories.-Geography:...
thickets that grew closest to a human constructed water development. White-throated woodrats were trapped least often in habitat dominated by creosotebush and furthest away (distance not given) from the water development. No white-throated woodrats were trapped at a nearby dry water development.
White-throated woodrats also occupied a human constructed desert riparian habitat at No Name Lake on the Colorado River Indian Reservation on the Arizona side of the Colorado River
Colorado River
The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...
. The area was cleared of nonnative tamarisk (Tamarix spp.) and 80% of the area was planted with native Fremont cottonwood and honey mesquite. Other vegetation included Goodding's willow Salix gooddingii
Salix gooddingii
Salix gooddingii is a species of willow known by the common name Goodding's willow, or Goodding's black willow. It was named for its collector, Leslie Newton Goodding....
, blue paloverde (Parkinsonia florida
Parkinsonia florida
Parkinsonia florida is a species of palo verde native to the southwestern United States and northwestern Mexico...
), big saltbush (Atriplex lentiformis
Atriplex lentiformis
Atriplex lentiformis is a species of saltbush.-Distribution:...
), and California fan palm (Washingtonia filifera
Washingtonia filifera
Washingtonia filifera , with the common names California Fan Palm , Desert Fan Palm, Cotton palm, and Arizona Fan Palm. It is a palm native to southwestern North America between an elevation range of , at seeps, desert bajadas, and springs where underground water is continuously available...
).
Coarse woody debris
Habitat with abundant coarse woody debrisCoarse woody debris
Coarse woody debris is a term used in English-speaking countries for fallen dead trees and the remains of large branches on the ground in forests. Some prefer the term coarse woody habitat . A dead standing tree is known as a snag and provides many of the same functions as coarse woody debris...
is preferred by white-throated woodrats for cover (see Cover). In pinyon-juniper woodlands at the Piñon Canyon Maneuver site near Trinidad, Colorado
Trinidad, Colorado
The historic City of Trinidad is a Home Rule Municipality that is the county seat and the most populous city of Las Animas County, Colorado, United States...
, white-throated woodrats were captured most often in areas with coarse woody debris. In an actively flooded riparian channel and floodplain at Montezuma Castle National Monument, white-throated woodrat occurrence was significantly (P<0.05) greater in areas containing coarse woody debris than areas without coarse woody debris.
In a pinyon-juniper woodland in the Gila National Forest, New Mexico, white-throated woodrats responded favorably to mechanical treatments that increased the amount of coarse woody debris. Of 4 treatments (untreated; bulldozed/piled/burned; bulldozed; and thinned), white-throated woodrats were most abundant on bulldozed plots and thinned plots, where slash accumulations were 2.5 to 3 times greater than on other plots. On bulldozed plots, Colorado pinyon, one-seed juniper, and alligator juniper trees were pushed over and left in place. On thinned plots, Colorado pinyon and juniper were cut to a minimum spacing of 20.0 feet (6.1 m) and left in place. The table below shows total numbers of woodrats on 4 plots :
White-throated woodrat density increased in a pinyon-juniper woodland in Grant County, New Mexico, where trees were uprooted and piled to improve livestock grazing. The felled trees provided white-throated woodrats with cover and building materials.
Cover requirements
White-throated woodrats must rely on self-constructed, ground-level shelter to lower the energetic costs of thermoregulation in extreme environments. White-throated woodrats typically use 2 types of shelter: houses, constructed at the base of plants, and dens in rock crevices. Other shelter types include holes and crevices in cutbanks along washes, subterranean burrows of other animals, piles of coarse woody debris, and human habitations and structures. Houses and dens are often maintained by successive generations of white-throated woodrats.Houses are built by white-throated woodrats at the base of trees, shrubs, and cacti or in piles of coarse woody debris. White-throated woodrats prefer to construct houses at the bases of plants that provide both adequate shelter and food. Houses are constructed of various materials and are typically 3 to 10 feet (1–3 m) in diameter and up to 3 feet tall. Dens function as houses but are located in rock crevices, rock fissures, and under boulder piles.
Houses and dens enclose a system of runways and chambers, including the white-throated woodrat's nest. The nest averages 8 inches (20 cm) in diameter and is composed of soft, fine material including grass, shredded prickly-pear fibers, or juniper bark.
Building materials
White-throated woodrats use locally available building materials to construct houses. In wooded areas, white-throated woodrats use sticks and other debris, and in deserts, parts of cacti, catclaw acacia, mesquite, and yucca are typically used. Cactus parts are preferred building materials; preference for cacti is so strong that white-throated woodrat houses may not contain a proportionally representative sample of the surrounding plant community. Other building materials used by white-throated woodrats across their range include feces, bones, and human objects. Of 100 white-throated woodrat houses found on the Santa Rita Experimental Range, 75 different items were used for construction. The most commonly used building materials included mesquite, catclaw acacia, paloverde, desert ironwood (Olneya tesota), and creosotebush twigs; cholla joints and fruits; portions of prickly-pear where it was abundant; and juniper, pinyon pine, and oak twigs where they were abundant. Other items included horse, cow, and coyote dung, animal bones, stones, and human-discarded materials.Building materials are gathered near the white-throated woodrat's shelter. At McDowell Mountain Regional Park, Arizona, white-throated woodrats gathered 30% of house building materials within 33 feet (10 m) from their shelter. Houses and dens are altered and refurbished during the year using new and old building materials.
In Guadalupe Mountains National Park and the Lower Sonoran zone of Arizona, use of building materials depended on availability. Juniper leaves and berries were used most often in a pinyon-juniper woodland, and mesquite leaves and pods and Christmas cactus (Cylindropuntia leptocaulis
Cylindropuntia leptocaulis
Cylindropuntia leptocaulis, Desert Christmas cactus, Desert Christmas Cholla, and Tasajillo, is a cactus.-Distribution:...
) joints were used most often in a desert scrub habitat. In the Lower Sonoran desert of Arizona, white-throated woodrats favored some plants because of their structural and food values and favored other plants due to their availability. When available, cholla was used most often for building material due to its structural and food values. Mesquite sticks were used frequently. Although mesquite was seldom used for food, mesquite sticks were abundant at the base of plants so they were readily available. White bursage (Ambrosia dumosa) was very abundant and used for building material, even though plants were too small to shelter a white-throated woodrat den.
Shelter sites
Cover near the ground is an important criterion for white-throated woodrat shelter sites. In northern portions of their range, white-throated woodrats tend to construct houses at the bases of trees; in southern portions of their range, white-throated woodrats tend to construct houses at the bases of shrub-trees, shrubs, or cacti. When available, rocks are preferred by white-throated woodrats for shelter because they provide more protection from variations in ambient temperature than the base of plants.Plants
Although any tree, shrub, or cactus may be used by white-throated woodrats for shelter sites, the most commonly used plants are discussed below.White-throated woodrats construct houses at the base of live and dead fallen juniper trees in pinyon-juniper woodlands in Arizona, New Mexico, Utah, and Texas. The base of pinyons are occasionally used.
Mesquite is often favored by white-throated woodrats for shelter in habitat dominated by mesquite in New Mexico, Arizona, California, and Texas. In habitat dominated by mesquite and creosote bush
Creosote bush
Larrea tridentata is known as Creosote bush as a plant, chaparral as a medicinal herb, and as "gobernadora" in Mexico, Spanish for "governess," due to its ability for inhibiting the growth of nearby plants to have more water. In Sonora, it is more commonly called "hediondilla." It is a flowering...
in San Diego County, California
San Diego County, California
San Diego County is a large county located in the southwestern corner of the US state of California. Hence, San Diego County is also located in the southwestern corner of the 48 contiguous United States. Its county seat and largest city is San Diego. Its population was about 2,813,835 in the 2000...
, all white-throated woodrat houses were located at the bases of honey mesquite
Honey Mesquite
Prosopis glandulosa, commonly known as honey mesquite, is a species of small to medium-sized flowering tree in the legume family, Fabaceae. It is native to the Southwestern United States and Mexico, growing as far north as southern Kansas and as far east as the eastern fifth of Texas, where...
. Twenty to 26-foot tall (6–8 m) honey mesquite were preferred over 3 to 10 foot (1–3 m) tall honey mesquite, probably because they provided more shelter and abundant, accessible food. An exception in habitat dominated by mesquite occurred on the Santa Cruz river bottom near Tucson, Arizona, where white-throated woodrat houses were also built under netleaf hackberry, American black elderberry (Sambucus nigra
Sambucus nigra
Sambucus nigra is a species complex of elder native to most of Europe.It is most commonly called Elder, Elderberry, Black Elder, European Elder, European Elderberry, European Black Elderberry, Common Elder, or Elder Bush when distinction from other species of Sambucus is needed...
), skunkbush sumac (Rhus trilobata
Rhus trilobata
Rhus trilobata is a shrub in the sumac genus with the common names sourberry, skunkbush, and three-leaf sumac. It is native to the western half of Canada and the Western United States, from the Great Plains to California and south through Arizona extending into northern Mexico...
), bear grass (Nolina
Nolina
Nolina is a genus of tropical xerophytic flowering plants, with the principal distribution being in Mexico and extending into the southern United States. Some botanists have included the genus Beaucarnea in Nolina. In the APG III classification system, it is placed in the family Asparagaceae,...
spp.), or saguaro
Saguaro
The saguaro is a large, tree-sized cactus species in the monotypic genus Carnegiea. It is native to the Sonoran Desert in the U.S. state of Arizona, the Mexican state of Sonora, a small part of Baja California in the San Felipe Desert and an extremely small area of California, U.S...
.
In habitats where yucca are abundant white-throated woodrats use the base of yucca for shelter sites. On the Jornada Experiment Range in New Mexico, and the Black Gap Wildlife Management Refuge in Trans-Pecos Texas , white-throated woodrats built houses at the bases and fallen trunks of yucca. Soaptree yucca
Soaptree yucca
The Soaptree yucca is a perennial plant in the genus Yucca. It is native to southwestern North America, in the Sonoran Desert and Chihuahuan Desert in the United States , and northern Mexico .This plant grows from 1.2-4.5 m tall, with a sparsely branched trunk...
was used by white-throated woodrats in the lower Sonoran zone of the Lordsburg Plains in New Mexico and the San Simon Valley in Arizona.
Cholla and prickly-pear are often used by white-throated woodrats for cover because they provide excellent protection from predators, as well as food and water. One of the factors in white-throated woodrat shelter-site selection in McDowell Mountain Regional Park was presence of teddy bear cholla. In the Cholla Garden in Joshua Tree National Park
Joshua Tree National Park
Joshua Tree National Park is located in southeastern California. Declared a U.S. National Park in 1994 when the U.S. Congress passed the California Desert Protection Act , it had previously been a U.S. National Monument since 1936. It is named for the Joshua tree forests native to the park...
, white-throated woodrats depended on stands of jumping cholla (Cylindropuntia fulgida) for cover, and in the Lower Sonoran zone of Arizona, most white-throated woodrat dens were found at the bases of cholla and prickly-pear.
In Guadalupe Mountains National Park
Guadalupe Mountains National Park
Guadalupe Mountains National Park is located in the Guadalupe Mountains of West Texas and contains Guadalupe Peak, the highest point in Texas at in elevation. It also contains El Capitan, long used as a landmark by people traveling along the old route later followed by the Butterfield Overland...
, white-throated woodrat distribution may be limited more by the presence of Mexican woodrats (N. mexicana) and the southern plains woodrat (N. micropus) than by habitat limitations. In areas not inhabited by Mexican woodrats and southern plains woodrats, the white-throated woodrat constructed houses at bases of prickly-pears. In areas where white-throated woodrats and southern plains woodrats lived in close proximity, white-throated woodrat constructed houses under honey mesquite.
In the Lower Sonoran zone of Arizona and New Mexico, white-throated woodrats commonly used the bases of catclaw acacia for shelter.
White-throated woodrats selected multiple-stemmed plants over single-stemmed plants and a dense, low canopy over a tall, thin canopy in habitat dominated by triangle bursage in Organ Pipe Cactus National Monument
Organ Pipe Cactus National Monument
Organ Pipe Cactus National Monument is a U.S. National Monument and UNESCO biosphere reserve located in extreme southern Arizona which shares a border with the Mexican state of Sonora. The park is the only place in the United States where the Organ Pipe Cactus grows wild...
in Arizona and New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
. White-throated woodrats selected house sites in reverse order of plant abundance: yellow paloverde 18.1 plants/ha, 6 houses; desert ironwood, 7.6 plants/ha, 14 houses; and organ pipe cactus, 5.0 plants/ha, 21 houses. Yellow paloverde was probably selected for shelter least often because it is a single-stemmed tree with a tall canopy; organpipe cactus (Stenocereus thurberi) was probably selected most often because it is a multiple-stemmed plant with many cylindrical stems branching near the ground from a central trunk, providing more cover.
Other shelter sites
In juniper woodlands in the high desert of southeastern Utah, white-throated woodrats occasionally denned under boulder crevices at the bases of vertical cliffs. In habitat dominated by brittle bush in Saguaro National Monument, all 103 white-throated woodrat dens were located within jumbles of rocks or under boulders. Ninety-one dens were located under boulders >7 feet (2 m) in diameter, and 12 dens were located under boulders <7 feet in diameter.White-throated woodrats occasionally use river banks, subterranean areas, or caves for shelter. In habitat dominated by honey mesquite and creosotebush at Carrizo Creek in San Diego County, white-throated woodrats sought cover either in river banks or subterranean burrows that were probably excavated by kangaroo rats (Dipodomys spp.). Lack of stick houses may have been due to a harsh summer climate, ease of burrowing in loose sand, scarcity of building materials, or adequate overhead protection by honey mesquite. River banks were 6 to 15 feet (2–5 m) high, and burrows were excavated at various heights from the bottom. Hole diameter was 3.5 to 7 inches (8.9–18 cm). White-throated woodrats also dwelled in subterranean burrows with as many as 8 openings, covered with a few small twigs, at the bases of honey mesquite. In a similar habitat type in the Mesilla Valley of New Mexico, white-throated woodrats denned in sand dunes created by banner-tailed kangaroo rats (D. spectabilis) around honey mesquite.
Timing of major life events
The white-throated woodrat is a small rodent measuring an average of 12.9 inches (32.8 cm) and weighing an average of 188 g for females and 224 g for males. With the exception of lactating females, white-throated woodrats are solitary and occupy separate houses. They are primarily nocturnal and are active year-round. According to Brown and Zeng, maximum longevity for the white-throated woodrat is 45 months, and according to Newton, maximum longevity is 72 months.The mating season of white-throated woodrats varies across their range. In Arizona, the mating season is from January to August. In Big Bend National Park, Texas, mating occurs at least from January to November and may occur year-round. In California, the mating season is in February and March, according to Rainey, and in March, April, and possibly May, according to Schwartz and Bleich. The mating system of the white-throated woodrat is polygynous.
Gestation for white-throated woodrats lasts 37 to 38 days, and young are most often born in spring and early summer. In Arizona, mean litter sizes were 1.95 young/litter (n=93 litters) and 2.5 young/litter (n=27 litters).
Young white-throated woodrats are weaned 62 to 72 days after birth and reach sexual maturity 166 to 176 days after birth. Weaning and sexual maturity of the subspecies Neotoma albigula venusta in western Arizona, Sonora, and Baja California occur earlier: young are weaned between 27 and 40 days, and reach sexual maturity 80 to 87 days after birth. In Joshua Tree National Monument, California, young white-throated woodrats establish their own dens by August and September, several months after birth.
Descriptions of the home home range of the white-throated woodrat are lacking. The home range of 1 immature female white-throated woodrat on the Coconino National Forest, Arizona, was 47,760 ft² (4,437 m²).
White-throated woodrat density may be governed by the number of suitable plants available for shelter, food, and water. In Joshua Tree National Monument, there was a significant (P<0.001) positive relationship between white-throated woodrat density and teddybear cholla density, which provided shelter, food, and water. In the Mesilla Valley of southern New Mexico, white-throated woodrat density was more dependent on plants that provided sufficient water and food than on plants that provided shelter.
Food habits
White-throated woodrats are opportunistic and primarily herbivorous [31]. Their diet consists of seeds, fruits, green portions of plants, flowers, small amounts of grass, and occasionally beetles (Coleoptera), ants (Hymenoptera), and reptiles. Some of the most commonly consumed plants across the white-throated woodrat's range include mesquite flowers, leaves, seeds, and bark, cacti flowers, stems, and fruits, and yucca leaves.Foods eaten by white-throated woodrats depend on availability. In Great Basin
Great Basin
The Great Basin is the largest area of contiguous endorheic watersheds in North America and is noted for its arid conditions and Basin and Range topography that varies from the North American low point at Badwater Basin to the highest point of the contiguous United States, less than away at the...
scrub desert and juniper woodlands in northern Arizona (Coconino County
Coconino County, Arizona
-2010:Whereas according to the 2010 U.S. Census Bureau:*61.7% White*1.2% Black*27.3% Native American*1.4% Asian*0.1% Native Hawaiian or Pacific Islander*3.1% Two or more races*5.2% Other races*13.5% Hispanic or Latino -2000:...
) white-throated woodrat diet was 29% yucca, 24% juniper, 7% rabbitbrush (Chrysothamnus spp.), 6% sumac, 5% Apache-plume (Fallugia spp.), 4% sagebrush (Artemisia spp.), 4% saltbush, and 3% ephedra (Ephedra spp.). In the Lower Sonoran zone of southern Arizona (Santa Rita Experimental Range), cacti and mesquite were the primary foods eaten. For a complete list of foods eaten by white-throated woodrats in the Santa Rita Experimental Range, see Vorhies and Taylor. In the southern Great Basin, Navajo yucca (Y. baileyi) is an important food for the white-throated woodrat.
White-throated woodrats require large amounts of water obtained through various xerophytic plants, especially cacti. In Organ Pipe National Monument, white-throated woodrats relied heavily on teddybear cholla, buckhorn cholla (Cylindropuntia acanthocarpa), jumping cholla, and goatnut (Simmondsia spp.) for water. In Coconino County, white-throated woodrats obtained water from evergreen species (Ephedra spp., Yucca spp., and Juniperus spp.), which maintained a high year-round water content.
The white-throated woodrat diet varies seasonally. In Coconino County, white-throated woodrats ate a variety of plants, including deciduous shrubs, during warm, wet months when plant moisture was high. During cool, dry months, their diet was restricted largely to evergreen plants. Regardless of season, white-throated woodrats preferred to eat evergreen species. At Carrizo Creek, honey mesquite leaves, flowers, and fruits were the main foods eaten from the end of March until the end of summer. After honey mesquite lost its leaves, white-throated woodrats subsisted on stored beans, bark, and stems.
Some white-throated woodrats store food in their houses. Of 30 white-throated woodrat dens found in Doña Ana County, New Mexico
Doña Ana County, New Mexico
-2010:Whereas according to the 2010 U.S. Census Bureau:*74.1% White*1.7% Black*1.5% Native American*1.1% Asian*0.1% Native Hawaiian or Pacific Islander*3.0% Two or more races*18.5% Other races*65.7% Hispanic or Latino -2000:...
, 77% contained stored food. The average weight of stored food was 2.2 pounds (1.0 kg)/den, range 0.1 to 9.3 pounds (0.05–4.2 kg)/den). Most stored food consisted of mesquite beans and cacti and forb seeds. In general, white-throated woodrats collect food within a 98- to 164-foot (30–50 m) radius of their dens.
Predators
Predators of white-throated woodrat include weasels (Mustela spp.), bobcatBobcat
The bobcat is a North American mammal of the cat family Felidae, appearing during the Irvingtonian stage of around 1.8 million years ago . With twelve recognized subspecies, it ranges from southern Canada to northern Mexico, including most of the continental United States...
s (Lynx rufus), Ring-tailed Cat
Ring-tailed Cat
The ringtail is a mammal of the raccoon family , native to arid regions of North America. It is also known as the ringtail cat, ring-tailed cat or miner's cat, and is also sometimes mistakenly called a "civet cat"...
s (Bassariscus astutus), coyotes (Canis latrans), American Badger
American Badger
The American badger is a North American badger, somewhat similar in appearance to the European badger. It is found in the western and central United States, northern Mexico and central Canada, as well as in certain areas of southwestern British Columbia.Their habitat is typified by open...
s (Taxidea taxus), Mexican spotted owls (Strix occidentalis lucida), Great Horned Owl
Great Horned Owl
The Great Horned Owl, , also known as the Tiger Owl, is a large owl native to the Americas. It is an adaptable bird with a vast range and is the most widely distributed true owl in the Americas.-Description:...
s (Bubo virginianus), bullsnake
Bullsnake
The bullsnake ' is a large non-venomous colubrid snake, widespread in the central part of the United States, northern Mexico, and southwestern Saskatchewan and Alberta Canada. It is currently considered a subspecies of the gopher snake '...
s (Pituophis catenifer sayi), and rattlesnake
Rattlesnake
Rattlesnakes are a group of venomous snakes of the genera Crotalus and Sistrurus of the subfamily Crotalinae . There are 32 known species of rattlesnake, with between 65-70 subspecies, all native to the Americas, ranging from southern Alberta and southern British Columbia in Canada to Central...
s (Crotalus spp.).
Further reading
- Harris, A. H. 1993. Quaternary vertebrates of New Mexico. pp. 179–107, in Vertebrate paleontology in New Mexico. New Mexico Museum of Natural History and Science, Bulletin 2.