Biology ETDs


A.L. Gennaro

Publication Date

Spring 5-12-1961


A total of 520 cotton rats, Sigmodon hispidus, was examined to determine the kind and amount of geographic variation of these animals in New Mexico.

The distributional history of Sigmodon hispidus in New Mexico may be revealed by a relationship between color variation of these animals and soil color of areas from which these animals were taken. This relationship suggests, firstly, that Sigmodon hispidus has occupied the southern Rio Grande Valley for a longer period of time than it has areas east of the Rio Grande Valley, and secondly, that Sigmodon hispidus has only recently occupied the Deming Plain.

Color variations of Sigmodon hispidus on the Deming Plain leads one to assume that Sigmodon hispidus of eastern parts of the Deming Plain moved into this areas from the southern Rio Grande Valley and that Sigmodon hispidus of western parts of the Deming Plain moved into this area from the west.




Sigmodon hispidus, Cotton Rat, Deming Plain, Rio Grande Valley

Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

J.S. Findley

Second Committee Member

C. Clayton Hoff

Third Committee Member

William C. Martin

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Biology Commons