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Species in this Guide: 44
Sonoran Desert Mammals
Created by: Katja Schulz
Cliff Chipmunk  Tamias dorsalis         View on EOL
Overview

General Description
Cliff chipmunk fossils about 2,300 and 8,000 years old have been found in caves in Utah and Nevada. The chipmunks still live in those states, in habitats where sagebrush, fourwing saltbush, chokecherry, wild rose, and cliffrose grow. In other parts of their range, they are found with a wide variety of plants, and their diets include seeds and fruits from many kinds of grasses, shrubs, forbs, and trees. They also feed on insects, frogs, salamanders, snakes, birds, and eggs. Four other chipmunk species share parts of their range. Where one or more other species occurs on a mountain, the cliff chipmunk usually is found at the lowest elevation, but where none of the others occurs, cliff chipmunks range right to the top of the mountain.

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species accountProject: Smithsonian Institution - North American Mammals  Source: Smithsonian Institution   CC License: by

Physical Description

Morphology

Tamias dorsalis is a smoky-gray chipmunk with dark stripes on its back. These dark stripes are more distinct on the summer fur than on the winter fur. It lacks the white stripes often found in the pelage of this genus. The flanks are light brown in color, and the undeparts are creamy-white. The tail is bushy with black on top and cinnamon brown underneath. The feet have a hint of yellow. The molt in May and June from winter to summer pelage occurs from anterior to posterior. Females tend to molt into their summer pelage in June and July, later than males, due to the engergy requirements of pregnancy and lactation. (Dunford, 1974; Hart, 1976; Hart, 1992; University of New Mexico, 1998)

Adults of this species average 70 g. Females are larger than males, weighing between 70 and 74 g. The smaller males weigh between 61 and 64.5 g. (Dunford, 1974; Hart, 1976; Hart, 1992; University of New Mexico, 1998)

The total length of T. dorsalis ranges between 217 and 249 mm, with the hind foot measuring between 34 and 37 mm. They have 22 teeth. Eight mammae are present on the females. (Hart, 1992)

There are several subspecies reported, and these subspecies are reported to have clinal variation which intergrades them phenotypically. The subspecies may be defined mainly by differences in body and skull dimensions, pelage characters, dental characeters, and differences in the baculum. (Hart, 1992)

Tamias dorsalis is sympatric with several other species of chipmunks, including T. canipes, T. cinereicollis, T. minimus, T. quadrivittatus, and T. umbrinus. However, all of these species have well defined white stripes on their fur, making it easy to distinguish them from T. dorsalis at a glance. (Hart, 1992)

The species is diagnosed by its baculum. This has a thin shaft, ranging in length from 2.64 to 3.69 mm. The distal half of the shaft is somewhat laterally compressed. The keel, which is 20% of the length of the tip, is low. The tip of the baculum is between 20% and 40% the length of the shaft, and forms an angle of 140 degrees with the shaft. (Hart, 1992)

Other Physical Features: Endothermic; Bilateral symmetry

Sexual Dimorphism: Female larger
Editor: Nancy Shefferly, Animal Diversity Web Staff, Editor: Chris Yahnke, University of Wisconsin Stevens Point, Author: Louise Venne, University of Wisconsin-Stevens Point  Source: The Regents of the University of Michigan and its licensors   CC License: by-nc-sa

Size
Sexual Dimorphism: Females are slightly larger than males.

Length:
Average: 217 mm males; 222 mm females
Range: 204-226 mm males; 212-235 mm females

Weight:
Average: 59.5 g males; 62.9 g females
Range: 54.5-63.8 g males; 58.8-66.7 g females;Project: Smithsonian Institution - North American Mammals  Source: Smithsonian Institution   CC License: by

Show/Hide iNaturalist Observations Map for this species. Source: iNaturalist