Antilocapra americana sonoriensis
Goldman, 1945
Sonoran Pronghorn
T1T1Global Rank
Very high - highThreat Impact
U.S. Fish & Wildlife Service, https://www.usa.gov/government-works
Identity
Unique IDELEMENT_GLOBAL.2.104902
Element CodeAMALD01012
Record TypeSPECIES
ClassificationSubspecies
Classification StatusStandard
Name CategoryVertebrate Animal
CITESAppendix I
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassMammalia
OrderArtiodactyla
FamilyAntilocapridae
GenusAntilocapra
Other Common Names
Sonoran pronghorn (EN)
Concept Reference
Hall, E. R. 1981a. The Mammals of North America, second edition. Vols. I & II. John Wiley & Sons, New York, New York. 1181 pp.
Taxonomic Comments
The distinctiveness of this subspecies remains to be ascertained (Hoffmeister 1986).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2021-03-29
Change Date1996-03-19
Edition Date2021-03-29
Edition AuthorsSchwartz, S. (2006, 2011), Flower, C. (2021)
Threat ImpactVery high - high
Range Extent5000-20,000 square km (about 2000-8000 square miles)
Number of Occurrences1 - 5
Rank Reasons
This subspecies has a small, reduced range in Arizona (US) and Sonora (Mexico). The Arizona population was nearly extirpated by severe drought in 2002, however, intensive conservation measures have helped the populations recover. In addition to the wild population, the Kofa and Sauceda populations in Arizona are stable to increasing. Population decline is attributed mainly to loss of habitat, habitat fragmentation, climate change, drought, and (in Mexico) probably poaching.
Range Extent Comments
Formerly throughout southern Arizona, US, and in Mexico south to Guaymas, Sonora. Presently in Yuma, Pima, and Maricopa counties, south of the Bill Williams River and west of the Baboquivari Mountains, southwestern Arizona, and in northwestern Sonora (Matthews and Moseley 1990, Hoffmeister 1986).
Historically, Sonoran pronghorn ranged from the area between the Baboquivari Mountains and the Santa Cruz River in the east; to the vicinity of present-day Interstate 10 and no farther than the Bill Williams River in the north; to the main coastline of the Gulf of California to near Kino Bay and east to Hermosillo in the south; and into the Imperial Valley of California and the northern Gulf of California Coast of Baja California in the west, a range of about 55,0000 mi2 (142,450 km2 ) (USFWS 2010).
Populations in Arizona include the Cabeza Prieta, Kofa and Sauceda populations. The Cabeza Prieta population is an endangered population which generally occurs south of Interstate 8, west of Highway 85, and east of the Copper and Cabeza Prieta Mountains. The Kofa population is an experimental population that is found within the larger nonessential experimental population area in the vicinity of Kofa National Wildlife Refuge, north of Interstate 8. The Sauceda population is an experimental population initiated in December, 2015 within the larger nonessential experimental population area in the vicinity of Barry M. Goldwater Range East, east of Highway 85.
Historically, Sonoran pronghorn ranged from the area between the Baboquivari Mountains and the Santa Cruz River in the east; to the vicinity of present-day Interstate 10 and no farther than the Bill Williams River in the north; to the main coastline of the Gulf of California to near Kino Bay and east to Hermosillo in the south; and into the Imperial Valley of California and the northern Gulf of California Coast of Baja California in the west, a range of about 55,0000 mi2 (142,450 km2 ) (USFWS 2010).
Populations in Arizona include the Cabeza Prieta, Kofa and Sauceda populations. The Cabeza Prieta population is an endangered population which generally occurs south of Interstate 8, west of Highway 85, and east of the Copper and Cabeza Prieta Mountains. The Kofa population is an experimental population that is found within the larger nonessential experimental population area in the vicinity of Kofa National Wildlife Refuge, north of Interstate 8. The Sauceda population is an experimental population initiated in December, 2015 within the larger nonessential experimental population area in the vicinity of Barry M. Goldwater Range East, east of Highway 85.
Occurrences Comments
Five populations are extant, three in Arizona, and two in northwestern Sonora, Mexico. Populations in Arizona include the Cabeza Prieta, Kofa and Sauceda populations. The Cabeza Prieta population is an endangered population which generally occurs south of Interstate 8, west of Highway 85, and east of the Copper and Cabeza Prieta Mountains. The Kofa population is an experimental population that is found within the larger nonessential experimental population area in the vicinity of Kofa National Wildlife Refuge, north of Interstate 8. The Sauceda population is an experimental population initiated in December, 2015 within the larger nonessential experimental population area in the vicinity of Barry M. Goldwater Range East, east of Highway 85.
Threat Impact Comments
Population decline is attributed mainly to loss of habitat, habitat fragmentation, climate change, and drought. Specific threats and stressors include mining; agriculture, livestock grazing, renewable energy development, habitat conversion, physical barriers, border activities, reduced availability of water, low annual rainfall, thermal stress, reduced forage quality, fire, increased cover of creosote bush, invasive plant encroachment, decreasing pollinator populations, military activity, disease interactions with cattle, lack of genetic diversity, recreation, poaching, and lack of redundancy of populations and small population side.
Ecology & Habitat
Description
Upperparts are reddish brown to tan; underparts, lower sides, rump, and two bands on the neck are white; neck has a short black mane; male has a black band along each side of the snout, a black patch on each cheek, and sometimes black bands on the neck; males and most females have horns (larger and usually forked in males); two toes on each hoofed foot.
Diagnostic Characteristics
Differs from other subspecies in smaller size, narrower skull width and rostrum, unpronounced frontal depression, and relatively small auditory bullae (see data in Hoffmeister 1986); however, the reported differences are based on small sample sizes and need to be confirmed when and if more specimens become available (Hoffmeister 1986).
Habitat
The physiography of Sonoran pronghorn habitat is characterized by broad alluvial valleys separated by block-faulted mountains. These valleys are partially filled with clay, silt and alluvium deposited from sheet erosion and ephemeral streams. The valleys are fairly level, with drainage to the north and west through a braided wash system in the center of the valleys. Mountain ranges generally run in a northwest to southeast direction. The range of Sonoran pronghorn in Arizona is approximately 1 million ha in size. Mean elevations of the valleys vary from 400 - 1,600 feet (122 - 488 m).
Sonoran pronghorn habitat is within the Lower Sonoran Desert life zone (Shreve and Wiggins 1964). They occur in two divisions in this life zone in Arizona; the first is the Arizona Upland subdivision of the Sonoran Desert, with a paloverde-saguaro association, and the second is the Lower Colorado subdivision of the Sonoran Desert, with primarily a creosote-bursage association. Sonoran pronghorn browse on palo verde (Parkinsonia microphylla), mesquite (Prosopsis spp.), ironwood (Olneya tesota), chain fruit cholla (Cylindropuntia fulgida), the lavenderflowered four o’clock (Ambronia villosa), and desert broom-rape, (Orobanche multiflora), white ratany (Krameria grayi), silverbush (Ditaxis spp.), spurge (Euphorbia spp.), marigold (Baileya spp.), noseburn (Stillingia linearifolia), wire-lettuce (Stephanomeria pauciflora), white bursage (Ambrosia dumosa), blazing star (Mentzelia spp), ocotillo leaves (Fouquieria splendens), triangle-leaf bursage (Ambrosia deltoidea), mistletoe (Phoradendron spp.), false filaree (Erodium texanum), poverty weed (Monolepis nuttalliana), wooly plantain (Plantago insularis), wild carrot (Daucus pusillus), Arizona blanket-flower (Gaillardia arizonica), careless weed (Amaranthus palmeri), ragweed (Ambrosia spp.), brome (Bromus spp.), and broom snakeweed (Guterrezia sarothrae), buckwheat (Eriogonum spp.), milkvetch (Astragalus spp.), and borage (Borago spp.) species (USFWS 2016).
Sonoran pronghorn habitat is within the Lower Sonoran Desert life zone (Shreve and Wiggins 1964). They occur in two divisions in this life zone in Arizona; the first is the Arizona Upland subdivision of the Sonoran Desert, with a paloverde-saguaro association, and the second is the Lower Colorado subdivision of the Sonoran Desert, with primarily a creosote-bursage association. Sonoran pronghorn browse on palo verde (Parkinsonia microphylla), mesquite (Prosopsis spp.), ironwood (Olneya tesota), chain fruit cholla (Cylindropuntia fulgida), the lavenderflowered four o’clock (Ambronia villosa), and desert broom-rape, (Orobanche multiflora), white ratany (Krameria grayi), silverbush (Ditaxis spp.), spurge (Euphorbia spp.), marigold (Baileya spp.), noseburn (Stillingia linearifolia), wire-lettuce (Stephanomeria pauciflora), white bursage (Ambrosia dumosa), blazing star (Mentzelia spp), ocotillo leaves (Fouquieria splendens), triangle-leaf bursage (Ambrosia deltoidea), mistletoe (Phoradendron spp.), false filaree (Erodium texanum), poverty weed (Monolepis nuttalliana), wooly plantain (Plantago insularis), wild carrot (Daucus pusillus), Arizona blanket-flower (Gaillardia arizonica), careless weed (Amaranthus palmeri), ragweed (Ambrosia spp.), brome (Bromus spp.), and broom snakeweed (Guterrezia sarothrae), buckwheat (Eriogonum spp.), milkvetch (Astragalus spp.), and borage (Borago spp.) species (USFWS 2016).
Reproduction
Breeds in summer and early fall (around late July to early October), probably mainly in late summer. Gestation probably lasts around 210-225 days. Births occur in mid-spring. Females give birth usually to twins (single fawns mainly from young females). Young are weaned by four months, but continue to follow mother during first winter. Some begin breeding at 1 year.
Terrestrial Habitats
Desert
Other Nations (1)
United StatesN1
| Province | Rank | Native |
|---|---|---|
| Arizona | S1 | Yes |
| California | SH | Yes |
Threat Assessments
| Threat | Scope | Severity | Timing |
|---|---|---|---|
| 2 - Agriculture & aquaculture | Large - restricted | Serious - moderate | High (continuing) |
| 2.3 - Livestock farming & ranching | Large - restricted | Serious - moderate | High (continuing) |
| 2.3.2 - Small-holder grazing, ranching or farming | Large - restricted | Serious - moderate | High (continuing) |
| 3 - Energy production & mining | Restricted (11-30%) | Moderate - slight | High (continuing) |
| 5 - Biological resource use | Restricted (11-30%) | Moderate or 11-30% pop. decline | High (continuing) |
| 5.1 - Hunting & collecting terrestrial animals | Restricted (11-30%) | Moderate or 11-30% pop. decline | High (continuing) |
| 6 - Human intrusions & disturbance | Small (1-10%) | Slight or 1-10% pop. decline | High (continuing) |
| 6.1 - Recreational activities | Unknown | Unknown | Unknown |
| 6.2 - War, civil unrest & military exercises | Small (1-10%) | Slight or 1-10% pop. decline | High (continuing) |
| 8 - Invasive & other problematic species, genes & diseases | Large (31-70%) | Serious - moderate | High (continuing) |
| 8.1 - Invasive non-native/alien species/diseases | Large (31-70%) | Serious - moderate | High (continuing) |
| 8.2 - Problematic native species/diseases | Restricted (11-30%) | Slight or 1-10% pop. decline | High (continuing) |
| 11 - Climate change & severe weather | Pervasive (71-100%) | Extreme - serious | High (continuing) |
| 11.1 - Habitat shifting & alteration | Pervasive (71-100%) | Serious or 31-70% pop. decline | High (continuing) |
| 11.2 - Droughts | Pervasive (71-100%) | Extreme - serious | High (continuing) |
Roadless Areas (1)
Arizona (1)
| Area | Forest | Acres |
|---|---|---|
| Tumacacori | Coronado National Forest | 44,594 |
References (6)
- Hall, E. R. 1981a. The Mammals of North America, second edition. Vols. I & II. John Wiley & Sons, New York, New York. 1181 pp.
- Hoffmeister, D. F. 1986. Mammals of Arizona. University of Arizona Press and Arizona Game and Fish Department. 602 pp.
- Matthews, J.R. and C.J. Moseley (eds.). 1990. The Official World Wildlife Fund Guide to Endangered Species of North America. Volume 1. Plants, Mammals. xxiii + pp 1-560 + 33 pp. appendix + 6 pp. glossary + 16 pp. index. Volume 2. Birds, Reptiles, Amphibians, Fishes, Mussels, Crustaceans, Snails, Insects, and Arachnids. xiii + pp. 561-1180. Beacham Publications, Inc., Washington, D.C.
- U.S. Fish and Wildlife Service (USFWS). 1990. Endangered and threatened species recovery program: report to Congress. 406 pp.
- U.S. Fish and Wildlife Service (USFWS). 2010. Endangered and threatened wildlife and plants: Establishment of a nonessential experimental population of Sonoran pronghorn in southwestern Arizona. Federal Register 75(23):5732-5745.
- U.S. Fish and Wildlife Service (USFWS). 2011. Endangered and Threatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of Sonoran Pronghorn in Southwestern Arizona. Federal Register 76(87):25593-25611.