Taxonomy And Distribution Of Pocket Gophers Genus Thomomys In Southeastern Arizona

Author : Edward A. Goldman
Publisher : Forgotten Books
ISBN 13 : 9781330306635
Total Pages : 41 pages
Book Rating : 4.3/5 (66 download)

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Download or read book The Pocket Gophers (Genus Thomomys) Of Arizona written by Edward A. Goldman and published by Forgotten Books. This book was released on 2015-06-15 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from The Pocket Gophers (Genus Thomomys) Of Arizona In such places the burrows may be close together, with many mounds of excavated earth dotting the surface and tunnels interspersed. Numerous mounds may mark the operations of one or several individuals, but studies indicate that each burrow occupant, male or female, is solitary, except during the mating season and during the time that the young must remain in the same tunnels with their mother. Colonies may be more or less isolated by areas of nearly impervious soil or by rock formations, with breeding connections between them uncertain. Below the upper walls of the Grand Canyon one form, muralis, was found living in isolated strips of soil only a few feet wide, bounded above and below by vertical cliffs about 300 feet high. It presents rather well marked characters, and in this and a few similar cases the use of full specific names seems warranted, although the close relationship to a neighboring form is also clearly evident. Response to environmental conditions is shown by the marked tendency of pocket gophers to assume the colors of the soils in which they burrow. This tendency is shared with many other mammals, but is especially noteworthy in the forms of the Thomomys bottae group. Pocket gophers of this group inhabiting light-colored sand are usually light shades of buff, varying to almost white; those living in reddish soils assume rufescent tones; and those from blackish terrain, especially dark volcanic soils, are usually deeper reddish or dark brown, and may vary to black in some specimens. Occasional melanistic individuals may occur anywhere, but black or blackish specimens are more prevalent in lava areas. Pocket gophers inhabiting soft, sandy ground or alluvial bottomlands, where food is more abundant, or more accessible, tend to be larger than those inhabiting more rocky or sterile areas. Thomomys Baileyi Group The Thomomys baileyi group (fig. 2), as recognized, embraces several races ranging in western Texas, parts of southern New Mexico (except the Rio Grande Valley), northern Chihuahua, and west to southeastern Arizona, where the group is represented by T. b. mearnsi. In some of the more important characters these races agree with those of the bottae group, but the zygomata are slender with slight expansion of the maxillary arm near the line of contact with the jugal, the rostrum is of shallow depth, and the upper incisors are strongly procumbent. Representatives of the two groups taken in the same vicinity appear to be distinct. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.