Sunday 19 May
Nelson's antelope squirrel (Ammospermophilus nelsoni)
What’s the World’s Favourite Species?Find out here.
Nelson's antelope squirrel fact file
- Find out more
- Print factsheet
Nelson's antelope squirrel description
A highly sociable and conspicuous species, groups of Nelson’s antelope squirrels (Ammospermophilus nelsoni) are commonly seen scampering across the grassy hills of San Joaquin Valley, California (3) (4). This diminutive, ground-dwelling rodent has a cylindrical body with short, yet robust, legs; small, rounded ears and a large, bushy tail (5) (6). Touch sensitive whiskers protrude from the snout and white rings surround the large eyes, which are positioned on the side of the head to a provide a broad field of vision (5). The pelage is a buffy-tan and reddish-brown colour, with white stripes extending down the sides of the body, towards a light greyish tail (3) (6). When feeding, Nelson’s antelope squirrel assumes a distinctive posture, squatting on its rear limbs with the tail cocked behind the back, whilst holding its food in the forepaws. Morsels of food are chiselled with a pair of enlarged incisors and broken down by abrasive cheek teeth (5).
- Also known as
- San Joaquin antelope ground squirrel, San Joaquin antelope squirrel.
- Male head-body length: 23.4 – 26.7 cm (2)
- Female head-body length: 23 – 25.6 cm (2)
- 142 – 179 g (2)
The Nature Conservancy:
- Relating to the sediment deposited by flowing water, as in a riverbed, flood plain, or delta.
- The degree to which a species or taxonomic group is confined to a single region.
- The state of being pregnant; the period from conception to birth.
- Hibernation is a winter survival strategy characteristic of some mammals in which an animal’s metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer.
- The coat of a mammal, composed of fur, hair or wool, covering the bare skin.
IUCN Red List (March, 2010)
Smithsonian National Museum of Natural History (March, 2010)
- Nowak, R.M. (1999) Mammals of the World. The John Hopkins University Press, Baltimore.
- Best, T.L., Titus, A.S., Lewis, C.L. and Caesar, K. (1990) Ammospermophilus nelsoni. Mammalian Species, 367: 1-7.
- Macdonald, D.W. (2009) The Encyclopedia of Mammals. Oxford University Press, Oxford.
U.S Fish and Wildlife Service. (1998) Recovery Plan for Upland Species of the San Joaquin Valley, California. Portland, USA. Available at:
- Chappell, M.A. and Bartholomew, G.A. (1981) Activity and thermoregulation of the antelope ground squirrel Ammospermophilus leucurus in winter and summer. Physiological Zoology, 54: 215-223.
The Animal Ageing and Longevity Database (March, 2010)
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
Nelson's antelope squirrel biology
Most active at dusk and dawn, Nelson’s antelope squirrel shelters in burrows during the hotter parts of the day. Extensive networks of burrows with up to six openings may be dug under tussocks of vegetation, or the old burrows of other ground-dwelling mammals may be re-used (6). Although many ground squirrels hibernate in their burrows during winter months, Nelson’s antelope squirrel is active year round, reducing its body temperature during cooler periods to save energy expenditure (6) (7). For most of the year, green vegetation forms the bulk of its diet, but during the dry season, it commonly forages for insects (1). Food is carried in cheek pouches and may be cached in burrows or under rocks, and consumed later when food is in short supply (3).
Breeding takes place over winter, when mature females will typically mate with several males (5) (6). A single litter of around nine infants is produced after a gestation period of around 26 days, with birthing coinciding with a peak in green vegetation productivity (1) (6) (8). Juveniles develop rapidly, becoming independent after three to four weeks, but most juveniles will not live beyond one year due to high levels of predation (5) (8). Juveniles usually stay within the home range of the family, but some will travel up to one kilometre to find a mate (4).Top
Nelson's antelope squirrel range
Historically, Nelson’s antelope squirrel had a fairly large range, estimated at around 14,000 square kilometres, across central California in the United States (6). However, this species has disappeared from many areas, and is now largely confined to the western San Joaquin Valley and bordering valleys to the west in the inner Coast Ranges (1). The species’ total range is now estimated at less than 3,000 square kilometres, of which only 400 square kilometres are described as good quality habitat (6). The bulk of the population is found at Elk Hills and on the Carrizo and Elkhorn Plains in Kern County, while the only significant populations in the northern part of the species’ range are at the Panoche and Kettleman Hills (1).Top
Nelson's antelope squirrel habitatTop
Nelson's antelope squirrel status
Nelson's antelope squirrel is classified as Endangered (EN) on the IUCN Red List (1).Top
Nelson's antelope squirrel threats
The principal reason behind the dramatic decline of Nelson’s antelope squirrel is the loss of its habitat to agricultural encroachment, urbanisation, overgrazing by livestock, and oil and gas exploration. Now present in only 20 percent of its former range, Nelson’s antelope squirrel is extremely vulnerable to further habitat loss. In public owned reserves this rare species is protected from further declines, but in private owned areas, where the future management is uncertain, its habitat is still threatened. The use of insecticides on agricultural pests has also been identified as a further threat to Nelson’s antelope squirrel, due to loss of prey, while the historical use of rodenticides for the control of ground squirrels may have also contributed to the decline (1) (6).Top
Nelson's antelope squirrel conservation
Nelson’s antelope squirrel has already benefited from several conservation measures aiming to protect its vulnerable habitat. Several reserves have been created within the San Joaquin valley, an area defined by a high degree of endemism, including the Carrizo Plain National Monument and the Elkhorn Plain Ecological Preserve. This has offered Nelson’s antelope squirrel some sanctuary; however, several sites with substantial populations still receive no form of protection. Foremost in the drive to save this species should be the establishment of further protected areas in the Panoche and Kettleman hills and on the San Joaquin valley floor (1). Furthermore, livestock grazing of natural grasslands should be limited, while further surveys and monitoring of the density of this curious species is also required (6).Top
Find out more
For more information on the conservation of the San Joaquin Valley:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.