Gray-footed chipmunks, Tamias canipes, are found in the Sacramento, White, Gallinas, Jicarilla, Captain, and Guadalupe mountains of southeastern New Mexico. They also occur in Texas in the Guadalupe and Sierra Diablo mountains in the trans-Pecos region. (Best, et al., 1992; Hafner, 1995; Naturserve, 2005)
Tamias canipes is mainly a terrestrial, forest-dwelling chipmunk found in coniferous forests, dense mixed oak/pine/fir forests, pinyon-juniper woodlands, and brushy hillsides with rocky crevices. These chimpmunks prefer areas with an abundance of oaks, pines, and firs, where fallen trees and rocks crevices provide a place for nesting and hiding from predators. Nests are usually formed in cavities of downed timber and even underground among the roots of decaying tree stumps.
The species is found mostly at elevations of 1600 m to 3600 m, but will descend to lower zones such as the lava flows of the Carrizozo Malpais in the Tularosa Valley of New Mexico. (Best, et al., 1992; Naturserve, 2005; "Tamias canipes", 1993)
The distinguishing character of T. canipes is the gray coloring on the dorsal surface of the hind feet, hence the origin of its common name-- gray-footed chipmunk. This small chipmunk is grayish in color overall, with four whitish stripes and five brownish stripes on the lateral sides of the head, as well as 2 white and 3 brown stripes on each side of the animal. The shoulders, nape of the neck, rump, and thighs often have a wash of smoke gray color. There are dorsal stripes of black or brown, but there are also lighter stripes, with the inner stripes being smoke gray and the outer stripes being grayish-white. The tail color is black dorsally and reddish brown underneath. The ventral portion of the pelage is creamy white. Winter pelage is similar to summer pelage, except with more gray color dorsally and paler on the sides.
There is geographical variation in T. canipes, with some populations being bigger in size or darker in color than other populations in different mountain ranges. Within the species, weights are commonly between 65 and 75 g. For the Sacramento Mountain populations, total length varies between 227 and 264 mm. Tail length comprises 91 to 108 mm of the total length. The hind foot length averages 34.6 mm, with individuals ranging between 34.0 and 36.0 mm. In the Texas Guadalupe Mountains and New Mexico White Mountains, individuals tend to be smaller. Total length ranges between 210 and 250 mm, with tails measuring 92 to 115 mm. Hind foot length is smaller in these populations as well, measuring 32 to 35 mm.
As is the case in many chipmunks, females are larger than males. (Best, et al., 1992; Wilson and Ruff, 1999)
The dental formula is 1-0-2-3/ 1-0-1-3 for a total of 22 teeth. (Schmidly, 1994)
Because they hibernate, these animals are heterothermic. Body temperature decreases during the winter months while an individual is torpid. However, body temperature remains relatively constant during this period. In the summer, when the animals are active, body temperature is higher. Again, the temperature remains constant. This constant body temperature, varying seasonally, makes these animals both heterothermic and homoiothermic endotherms. (Best, et al., 1992; Wilson and Ruff, 1999)
The mating system of this species has not been described. However, most members of the genus Tamias breed polygynously. It is likely that these chipmunks are similar. (Wilson and Ruff, 1999)
Female gray-footed chipmunks produce one litter of about 4 young each year, between mid-May through August. Not much else is known about the breeding habits of this species. However, we can generalize from other species in the genus, as most chipmunks follow similar patterns. (Best, et al., 1992)
In most species of Tamias, females enter estrus shortly after they emerge from hibernation in the spring. Gestation lasts about one month. Lactation may occur for one to two months, depending upon the species. Young typically become independent in the season of their birth, and are capable of breeding the following spring. If this pattern holds for T. canipes, there is little time for young born in August to accumulate food caches to supply them through the winter months. (Wilson and Ruff, 1999)
The parental habits of this species have not been reported. However, in chipmunks the female typically cares for her young in a burrow or nest until the young are able to fend for themselves. Males play no role in parental care. (Wilson and Ruff, 1999)
Adult size of T. canipes is reached by late summer/early autumn, which leaves little time for the year’s offspring to store food before winter weather approaches. This may contribute to high mortality of young each year. (Best, et al., 1992)
Although data for T. canipes are not available, other species of chipmunk are not known to reach highly advanced ages. In captivity, some chipmunks may live as long as 10 years. Maximum lifespan in the wild is probably shorter, reaching about 8 years. Limits to longevity in T. canipes are probably similar. (Wilson and Ruff, 1999)
These diurnal mammals are most active shortly after sunrise. It is at this time that they do most of their foraging and feeding. Tamias canipes is primarily terrestrial, making its home in thick brush and rock crevices. Although they generally retreat underground when threatened, they are known to sometimes climb trees. (Best, et al., 1992; Wilson and Ruff, 1999)
These animals hibernate (or at least remain underground) during the cold weather. Unlike many hibernating mammals, they do not put on large stores of fat, and so must rely on food they have cached throughout the year to sustain them during the winter months. (Best, et al., 1992)
Although data are lacking for this species, most chipmunks are somewhat sedentary and territorial. It is likely that these animals fit the pattern so common in their genus. (Wilson and Ruff, 1999)
The size of T. canipes home ranges has not been reported. However, few species of chipmunks have ranges that excede one hectare in size. (Wilson and Ruff, 1999)
Gray-footed chipmunks make chipping sounds, described as a light “chipper” or a lower “chuck-chuck-chuck”. When they sense danger they are quiet. However, they also have an alarm call, much like a shrill version of the “chipper” sound, due to the closer intervals of the vocalization peaks. (Best, et al., 1992; "Tamias canipes", 1993; "Gray-footed Chipmunk", 1997)
In addition to vocalizations, we can assume that these chipmunks are like other members of their genus, in that they also communicate with visual signals such as tail and body position. They are also likely to use tactile communication while rearing their young and mating. The role of chemical communication in these animals has not been investigated. (Wilson and Ruff, 1999)
Diet varies and includes gooseberries and juniper berries, various acorns, seeds of the Douglas fir, currants, mushrooms, green vegetation, and insects. For the most part, acorns compose a significant portion of their diet, especially in the late summer and autumn. They hibernate, but usually do not gain extra weight. Instead, they subsist on cached supplies of acorns and other seeds. (Best, et al., 1992; Wilson and Ruff, 1999)
Gray-footed chipmunks are a common prey item for the carnivores of their forest habitat, including raptors like northern goshawks and other raptors. When aware of danger T. canipes hides in crevices or burrows, and pelage coloration helps themblend in with surrounding brush. (Best, et al., 1992; "Gray-footed Chipmunk", 1997)
Scattered acorn shells are the most common mark of feeding grounds, and cheek pouches often contain one large or several small acorns. Other wild seeds are also gathered, eaten, and stored. Tamias canipes's habit of gathering and storing seeds helps the progress of planting for many of the trees in their habitats. Tamias canipes serves as prey for carnivores. Chipmunks are also hosts to coccidian parasites Eimeria cohisensis and Eimeris dorsalis. (Best, et al., 1992)
Very little gray-footed chipmunk habitat is located in areas where humans reside, so there seems to be little positive or negative effect on human populations. Humans may receive an indirect benefit from these animals, in that their food caching behavior helps forests to regenerate. Humans do benefit from trees and other potential products of healthy forests. (Best, et al., 1992)
There is no reported negative impact of these animals on humans. (Best, et al., 1992)
Tamias canipes is listed by the IUCN Red list as LR/nt (lower risk/near threatened). The species has a patchy distribution, but there is nothing to suggest any immediate threat to its survival. The populations of T. canipes located in Texas occur in protected regions, whereas the populations in New Mexico and Sacramento mountains are not afforded any protection. (Best, et al., 1992; Naturserve, 2005; "Tamias canipes", 1993)
The genus name Tamias is Greek word meaning "a storer or distributor." The specific epithet canipes is derived from the Latin cantitia, which means gray in color and pes meaning foot. (Best, et al., 1992)
Mckie Maysha (author), California State Polytechnic University, Pomona, Rose Valerie (author), California State Polytechnic University, Pomona, John Demboski (editor, instructor), California State Polytechnic University, Pomona.
Nancy Shefferly (editor), Animal Diversity Web.
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. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
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.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
union of egg and spermatozoan
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.
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.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
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
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
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.
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.
Texas Tech University. 1997. Gray-footed Chipmunk. The Mammals of Texas - Online Edition. Accessed November 16, 2005 at http://www.nsrl.ttu.edu/tmot1/tamicani.htm.
Smithsonian Institution. 1993. Tamias canipes. Smithsonian National Museum of Natural History. Accessed November 16, 2005 at http://www.mnh2.si.edu/education/mna/image_info.cfm?species_id=394.
Best, T., J. Bartig, S. Burt. 1992. Tamias canipes. Mammalian Species, 411: 1-5.
Hafner, D. 1995. "Tamias canipes (V. Bailey 1902) Gray-footed chipmunk." (On-line). The World Conservation Union (IUCN). Accessed November 16, 2005 at http://www.iucn.org/themes/ssc/actionplans/northamericanrodents/5sciur5.pdf.
Levenson, H., R. Hoffmann, C. Nadler, L. Deutsch, S. Freeman. 1985. Systematics of the Holarctic Chipmunks (Tamias). Journal of Mammalogy, 66/2: 219-242.
Naturserve, 2005. "Comprehensive Report Species- Neotamias canipes" (On-line). NatureServe Explorer: An online encyclopedia of life. Accessed November 16, 2005 at http://www.natureserve.org/explorer/.
Schmidly, D. 1994. "Bison Species Account 050155; Gray-Footed Chipmunk" (On-line). Biota Information System Of New Mexico BISON. Accessed November 16, 2005 at http://www.bison-m.org/.
Wilson, D., S. Ruff. 1999. The Smithsonian Book of North American Mammals. Washington and London: The Smithsonian Institution Press in Association with the American Society of Mammalogists.