Antelope squirrels or antelope ground squirrels of the genus Ammospermophilus are sciurids found in deserts and dry scrub areas in the southwestern United States and northern Mexico.. They are a type of ground squirrel and are able to withstand hyperthermia and can survive at temperatures above 40 ° C (104 ° F).
There are currently four recognized species in the world, with one subspecies:
- The antelope horn of Harris, A. harrisii , is found in Arizona, New Mexico, and Sonora in Mexico.
- The San Joaquin antelope squirrel or Nelson antelope horn, A. nelsoni , is found in San Joaquin Valley, California.
- Texas antelope squirrel, A. interpres , found in Texas, New Mexico, and Mexico.
- A white-tailed antelope squirrel, A. leucurus , is found in the southwestern United States and the Baja California Peninsula.
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- The subspecies of the antelope squirrel España Santo, A. insularis , is found on Isla Españritu Santo.
All somewhat similar in appearance and behavior. They are about 14-17 cm (5.5-6.7 inches) long with a tail of 6-10 cm (2.4-3.9 inches), and weigh 110-150 grams (3.9-5.3 oz). The tail is a bit flat. They have a white line on both sides and nothing on the face. They live in burrows, which they dig themselves. They are diurnal, and do not hibernate (though they become less active during the winter), so they are fairly easy to see.
Video Antelope squirrel
Karakteristik umum
All the antelope squirrels have the same white line along the lateral side of the shoulder to the hip similar to the squirrel. However, unlike chipmunks, these distinctive white stripes do not extend to the animal's head. Squirrel antelope tails often curve forward on their backs. In the United States, these ground squirrels are found in dry deserts such as areas in the southwest. Different members of the genus Ammospermophilus have a unique adaptation that allows them to cope with extreme heat during the day and low temperatures at night. All squirrel antelope dug the ground for cover, but not all social beings. Each antelope squirrel has a white abdominal surface with little variation.
Maps Antelope squirrel
Unique morphology
The four unique species of the genus Ammospermophilus can be distinguished by several variations in size, weight, and appearance.
The white-tailed antelope horn ( leucurus )
A. leucurus has slightly longer legs and small round ears with reddish patterns on the outer surface of the limbs. Its length ranges from 194-239 millimeters (7.6-9.4 inches) with a tail length of 54-87 millimeters (2.1-3.4 inches). It weighs between 85-156 grams (3.0-5.5 oz).
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A. Harrisii mostly gray with some brown on the front and hind legs. Usually carrying a curved tail on the back. Its length ranges from 220 to 250 millimeters (8.7 to 9.8 inches) with a tail length of 74-94 millimeters (2.9-3.7 inches). They weigh 113-150 grams (4.0-5.3 oz).
A. interpres has a lateral tail hair with three black bands, the bottom of a grayish white tail, and they change from gray in winter to reddish gray in the summer. Its length ranges from 203-229 millimeters (8.0-9.0 inches) with a tail length of 50.8 to 76.2 millimeters (2.00-3.00 inches). Females weigh 84-115 grams (3.0-4.1 oz) and studs weigh 94-121 grams (3.3-4.3 oz).
Nelson antelope horn ( A. nelsoni )
A. nelsoni is brownish or brownish on the dorsal head and neck and the outer surface of the limbs. The tail is thicker than other ground squirrels with edges. Men are slightly larger than females with a length of 234-267 millimeters (9.2 to 10.5 inches) and 230-256 millimeters (9.1-10.1 inches), respectively. Summer and winter are different from the much darker winter pelang. These can be distinguished from white-tailed squirrels of larger size and more gray in their pelage. Their skulls also vary in the size of the zygomatic arch (larger in Nelson) and increased hearing bulls and nasal bones from A. nelsoni . The upper and upper first molar incisors are also greater.
Reproduction
The typical life span of wild deer squirrel is 2-4 years; though, in captivity they have been known to survive 11 years. Men and women mature sexually by the end of their first year. The reproductive season runs from February to March with usually one litter per year. Each litter contains between 5-14 younger who will wean about 8 weeks and make their first appearance on the ground. All the antelope squirrels give birth and take care of their children in burrows. However, they vary in the way they dig burrows. For example, a white-tailed squirrel dug a shallow hole under a brush or would use an abandoned burrow from a kangaroo rat. These squirrels are not monogamous and have been known to mate with many couples each season mating.
Habitat
An antelope squirrel is commonly found in dry and bush areas in the southern United States to Mexico. These areas are sandy with rocky terrain that provides land that can be buried for shade and to avoid the heat of the day. Temperatures in this region may exceed 37.8 Â ° C (100.0 Â ° F) during the day and require special adaptation by ground squirrels to survive. At night, temperatures in the desert and dry areas can fall below freezing which again requires adaptation to survive. Self-contained water supply is very limited. These areas may experience a long drought. A. harrisii does not require surface water in its reach but will drink on occasions from the hollow and the bird bath.
Diet
Land squirrels are the seeds that are important to spread in the dry desert and the shrubs that they live in. They participate in a behavior known as caching where seeds, fruits and vegetation are stored in burrows or hidden places for consumption at a later time. Ground squirrels are omnivores and will eat arthropods, insects, and carcasses when these food sources are available. Their food often rotates between green vegetation, fruit and seeds based on availability and season. All Antelope Squirrels carry their food in their cheek pouches for transport.
Behavior
A. leucurus has legs larger than other antelope squirrels, allowing them to quickly evade and escape from predators. They remain cool during the hot desert days by retreating into their burrows and limiting most activities to the early hours and late at night. Some white-tailed squirrels have been known to voice loud alarm calls when predators are nearby to warn relatives of incoming hazards.
A. nelsoni can work in temperatures up to 40 Ã, Â ° C (104Ã, Â ° F) and not hibernate, however, they will lower their core temperature to some degree of ambient temperature from the burrow. Likewise, they will decrease their activity level when food is scarce to save energy.
A. interpres lives in a very hot, dry climate and has adapted to lay flat (to maximize heat distribution) in a shady spot against cool soil. This allows Texas squirrels to be active during the hottest part of the day when most predators are off.
A. harrisii is the only antelope squirrel digging its own burrow instead of digging back another burrow. They cool off by saliva and hold their tails over their heads to provide shade. They also flatten themselves on the ground to cool down. During the winter, they use cached seeds but also continue to search for food.
References
Further reading
- Thorington, R. W. Jr. and R. S. Hoffman. 2005. The Sciuridae Family. pp.Ã, 754-818 in World Mammal Species, Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore.
Source of the article : Wikipedia
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