Arizona Shrew - Illustration by George Maleski

Arizona Shrew
Sorex arizonae

 

Shrews are the smallest land mammals known.1 The Arizona shrew is a medium-sized shrew, measuring four inches long and weighing 0.1 to 0.2 ounces.1 The fur is short, dense, and velvet- like, the color ranging from pale gray to grayish-brown.2 The snout is long and pointed, the eyes are small, and the ears are very inconspicuous.3

Habitat: The shrew is found primarily in rocky, narrow canyons1 with riparian areas bordered by pine-oak forests, usually near surface water.3 Dense leaf litter and downed logs provide cover for foraging shrews.1

Range: The Arizona shrew ranges from the mountains of southeastern Arizona (the Huachuca, Santa Rita, and Chiricahua mountains), the Animas Mountains in New Mexico, and the Sierra Madre Occidental of Chihuahua, Mexico.3

Diet:
Like moles and hedgehogs, the shrew is an insectivore.1 Shrews have a very high metabolic rate, and in order to avoid starvation, the shrew must consume one to two times its body weight daily. The shrew mainly feeds on insects, but is a voracious eater and will consume anything it can subdue, including earthworms, centipedes, snails, mice, and sometimes other shrews. The shrew locates its prey by using echolocation. The high clicks can confuse prey, making it easier to capture. The shrew also has mildly venomous saliva, which helps it overpower larger prey such as mice.1

Reproduction: Shrews are active year round. A female shrew can breed at three months old.1 The gestation period lasts twenty to twenty-five days, after which five to seven young are born.2 After about three weeks, the young shrews are weaned and taught to hunt. During this phase of development, a behavior called caravanning is exhibited. The young grab the base of the tail of the preceding individual, forming a train behind the mother. It is thought that this behavior allows the young shrews to safely explore and familiarize themselves with their surroundings.1

Status: The Arizona shrew is included on the Arizona Game and Fish Department's draft list of Wildlife of Special Concern. The shrew is also called Sensitive by the U.S. Forest Service.

The Arizona Shrew in Pima County: The Arizona shrew is sensitive to habitat loss and degradation related to livestock grazing and development of recreation sites.2 The shrew appears to have very narrow habitat requirements and disturbance may seriously jeopardize this species.2

 

References:

1. Van Pelt, William E. "Arizona Shrew (Sorex arizonae)." AZGF Nongame Field Notes. 8/23/99
Web site: www.gf.az.us/frames/fishwild/ngame_n.htm

2. BISON-M Taxonomy. Arizona Shrew (Sorex arizonae). 11/26/99 Web site: www.fw.vt.edu/fishex/nmex_main/species/050685.htm

3. Arizona Game and Fish Department. 1997. Sorex arizonae. Heritage Data Management System.


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