The bodies of Nelson's antelope squirrels are widest in the middle. They have small, rounded ears, short legs, and short tails. The back of their heads and necks and also the outside of their legs are dull yellowish-brown or tan. Their tails have thick hair and their underside is light grey or white. They have a light-colored stripe running along the side of the body starting at the shoulder. Males are a little bit bigger than females, measuring 234 to 267 mm, but usually around 249 mm. Females are 230 to 256 mm long, and usually around 238 mm. Nelson's antelope squirrels have different summer and winter fur colors. Their fur is darker in the fall and winter. The look a lot like white-tailed antelope squirrels, but are bigger and their fur is more gray. (Best, 1999; Brown and Williams, 2006; Merriam, 1983)
Nelson's antelope squirrels only live in California. They lives in the lowest parts of the San Joaquin valley, the Cuyama and Panoche valleys in San Luis Obispo county, and the Carrizo and Elkhorn plains. (Best, et al., 1990; Taylor, 1918)
Nelson's antelope squirrels are found in low, hot deserts. In North America, their habitats are found in Texas, New Mexico, Arizona, Nevada, and California. They live in dry grasslands and places with lots of shrubs. They can live in places with just a few or some shrubs and usually live with plants that live in dry environments. They like soils with clay, sand, and silt that are about 50 to 1100 meters elevation. They use burrows of kangaroo rats, so they might only live where there are kanagaroo rats. (Grinell and Dixon, 1918; Hawbecker, 1953; Merriam, 1898; Whitaker, et al., 2008)
Both male and female Nelson's antelope squirrels have multiple mates. Usually they find mates within the area where they usually live, but females will also travel up to 1 km away looking for a mate. ("Five Year Status Report- Ammospermophilus nelsoni", 1987; Hawbecker, 1947)
Nelson's antelope squirrels breed from late winter to early spring. The young develop inside the mother for 26 days. Then, females give birth in burrows underground. They have 6 to 11 young at a time, but usually around 9. The young stay underground for about the first 30 days after they are born. They drink their mother's milk. Sometimes they start eating solid food before they come out of the burrow, and other times not until after. Females get the young to stop drinking milk by refusing to give it to them and returning to the burrow less often. Males can breed earlier in their lives than females. (Best, et al., 1990; Best, 1999; Macdonald, 2009)
Young Nelson's antelope squirrels can't feed themselves right after they are born. Females give them milk and teach them to eat solid food, and males don't play a big role in caring for them. Mothers get their young to stop drinking their milk by staying farther away and not responding to them. Even after they stop drinking milk, mothers stay in contact by visiting their young and calling to them. (Best, et al., 1990)
In the wild, Nelson's antelope squirrels usually live for less than 1 year. Their babies and young are much more likely to die. They can live about 4 years in captivity, and the longest one ever lived in captivity was 5.7 years. About 80% of them die every year. They average lifespan is just 8 months. (Best, et al., 1990; Hawbecker, 1975)
Nelson's antelope squirrels live in small family groups of 6 to 8 squirrels. They are closely related to white-tailed antelope squirrels, who have strict social organization. They keep up their social organization using body language and fighting. Nelson's antelope squirrels are very similar to them in a lot of ways, and might do this too. ("Five Year Status Report- Ammospermophilus nelsoni", 1987; Belk and Smith, 1991; Best, et al., 1990; Best, 1999; Grinell and Dixon, 1918; Hawbecker, 1947; Hawbecker, 1953; Hawbecker, 1975)
Males and females usually live and travel in an area about 4.4 hectares. They tend to clump together within these areas in the best parts of their habitat. The farthest away from their home area males travel is 1,260 m and the fatherst away from their home area females travel is 900 m. (Best, et al., 1990)
Nelson's antelope squirrels mostly use hearing, smell, and sight. They look around before deciding to leave their burrows. They use their sense of smell to decide if there is danger, to find food, and communicate. They make alarm calls to warn others about nearby predators, especially if they are in closed-off areas. They make low-pitched trills that are actually made by shaking their body instead of their voice. Females also make this noise to communicate with their young. Nelson's antelope squirrels twitch their tails quickly when they are frightened or excited. (Best, et al., 1990; Best, 1999; Bolles, 1988)
Nelson’s antelope squirrels eat both animals and plants. Their biggest sources of food are insects, green plants, and seeds. They sometimes eat other small animals. They eat rodents, lizards and other Nelson's antelope squirrels that have died. They prefer to eat plants with a lot of water in them, since they don't live near water. Some plants they prefer are red-stemmed filaree and red brome. Other plants they eat are ephedra, clover, and locoweed. If there aren't many plants available that have a lot of water, they eat turpine weed. When plants and insects aren't available, they eat seeds. Nelson's antelope squirrels squat on their back legs with their tail up to eat, holding food in their front paws. (Hawbecker, 1947; Macdonald, 2009)
Nelson's antelope squirrels warn each other about predators and also avoid them. They hide in burrows of kangaroo rats, and check their surroundings carefully before they come out. Above ground, they hide in shrubs, and their light brown fur camouflages them in the desert. When they search for food, they stay close to the ground and move with short, quick jumps. Nelson's antelope squirrels use their sense of smell to get away from danger quickly. They communicate to each other about predators using alarm calls. They may also be able to understand warning calls of birds like horned larks and white-crowned sparrows. Their most important predators are American badgers, who dig into the burrows to eat both young and adults. They are also eaten by coyotes and kit foxes. ("Five Year Status Report- Ammospermophilus nelsoni", 1987; Best, et al., 1990; Brown and Williams, 2006)
Nelson's antelope squirrels are eaten by medium-sized predators. They get parasites inside and outside their bodies. They get tapeworms, roundworms (called Spirura infundibuliformis and Physaloptera spinicauda), and also thorny-headed worms. Outside their bodies, they get fleas and ticks. Nelson's antelope squirrels benefit from kangaroo rats, because they use their burrows. They further impact their habitat by continuing to burrow. They also collect seeds and disperse them. (Best, et al., 1990)
Nelson's antelope squirrels can get infected with diseases like western equine encephalomyelitis, St. Louis encephalitis, Powassan virus, and Modoc virus. However, they have never spread disease to humans. (Best, et al., 1990)
Nelson’s antelope squirrels are endangered, according to the IUCN Red List. A lot of their habitat has been destroyed because of farming and humans building bigger cities. They are also affected when animals raised by humans eat the plants they do, and by chemicals that are used to kill rodents and insects. California's Endangered Species Recovery Program has a list of ways to conserve them, like protecting their habitat and reintroducing them into protected areas. ("Five Year Status Report- Ammospermophilus nelsoni", 1987; Best, et al., 1990; Brown and Williams, 2006; Grinell and Dixon, 1918)
Divya Balaji (author), Yale University, Eric Sargis (editor), Yale University, Rachel Racicot (editor), Yale University, Tanya Dewey (editor), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.
an animal that mainly eats meat
flesh of dead animals.
uses smells or other chemicals to communicate
active at dawn and dusk
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
animals that generate their own body heat through metabolic processes.
parental care is carried out by females
an animal that mainly eats leaves.
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
an animal that mainly eats seeds
An animal that eats mainly plants or parts of plants.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats all kinds of things, including plants and animals
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
an animal that mainly eats dead animals
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
places a food item in a special place to be eaten later. Also called "hoarding"
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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Tevis, L. 1953. Stomach Contents of Chipmunks and Mantled Squirrels in Northeastern California. Journal of Mammalogy, 34/3: 316-324.
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