Article Contentsp.487p.488p.489p.490p.491p.492p.493p.494Issue Table of ContentsThe Southwestern Naturalist, Vol. 20, No. 4 (Jan. 10, 1976), pp. 423-594Volume Information [pp.587-593]Front MatterAnnotated Check List of the Alpine Vascular Plants of Specimen Mountain, Rocky Mountain National Park, Colorado [pp.423-435]Endomycorrhizal (Vesicular Arbuscular) Associations of Some Arid Zone Shrubs [pp.437-444]Ultrastructure of the Infraorbital and Preoperculomandibular Canal Neuromasts of the Silverjaw Minnow, Ericymba buccata (Pisces: Cyprinidae) [pp.445-459]Observations on Fishes Killed by Cold at Port Aransas, Texas, 11-12 January 1973 [pp.461-466]The Rough Earth Snake (Virginia striatula): Ecology of a Texas Population [pp.467-478]The Sandy-Beach Fauna of Mexico [pp.479-485]Structure and Location of Burrows of Yellow-Bellied Marmot [pp.487-494]The Rio Nazas as a Factor in Mammalian Distribution in Durango, Mexico [pp.495-502]Food Habits of the Western Diamondback Rattlesnake, Crotalus atrox, in Texas (Viperidae) [pp.503-515]Amphinemura reinerti, a New Stonefly from Northern Mexico (Plecoptera: Nemouridae) [pp.517-521]A Re-Evaluation of the Sceloporus scalaris Group (Sauria: Iguanidae) [pp.523-536]Feeding Adaptations of Hognose Snakes [pp.537-557]Frogs of the Rana pipiens Complex in the Northern and Central Plains States [pp.559-571]NotesRelationships between Dimensions, Weights, Volumes, and Calories of Some Sonoran Desert Seeds [pp.573-575]Occurrence and Implications of Heavy Parasitism on the Turtle Chelydra serpentina by the Leech Placobdella multilineata [pp.575-576]An Unusual Assemblage of Desmids from Wellborn, Texas [p.576]The Sympatric Occurrence of Three Species of Eubranchipoda in Douglas County, Kansas [pp.577-578]Distribution of Two Mating Call Types of the Plains Spadefoot, Scaphiopus bombifrons, in Southwestern United States [pp.578-582]Branchinecta paludosa (Müller) (Crustacea: Anostraca) in Northern Utah with Some Notes on Its Ecology [pp.582-585]Black and White Owl in Belize (British Honduras) [pp.585-586]Back Matter [pp.594-594]Southwestern Association of NaturalistsStructure and Location of Burrows of Yellow-Bellied MarmotAuthor(s): Gerald E. SvendsenSource: The Southwestern Naturalist, Vol. 20, No. 4 (Jan. 10, 1976), pp. 487-494Published by: Southwestern Association of NaturalistsStable URL: http://www.jstor.org/stable/3669865Accessed: 05/10/2009 11:30Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available athttp://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unlessyou have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and youmay use content in the JSTOR archive only for your personal, non-commercial use.Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained athttp://www.jstor.org/action/showPublisher?publisherCode=swan.Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printedpage of such transmission.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected] Association of Naturalists is collaborating with JSTOR to digitize, preserve and extend access toThe Southwestern Naturalist.http://www.jstor.orgTHE SOUTHWESTERN NATURALIST 20(4) :487-494 10 JANUARY 1976 STRUCTURE AND LOCATION OF BURROWS OF YELLTOW-BFELLTIED MARMOT GERALD E. SVENDSEN Department of Zoology and Microbiology, Ohio University, Athens Ohio 45701 and Rocky Mountain Biological Laboratory, Gothic-Crested Butte, Colorado 81224 ABSTRACT. The yellow-bellied marmot spends approximately 80% of its life in a burrow. Burrows provide protection from the rigors of the environment, pred- ators and other marmots. They provide a hibernaculum in winter and may func- tion as a nursery in summer. Selection of a burrow site is therefore an important aspect in the biology of marmots. Measurements were made on direction of exposure, angle of slope, drainage, soil type, topographic features, and vegetation. Home burrows occur on open grassy or herb-covered slopes of an angle of 15 ?-40?, facing in a northeasterly or southwesterly direction, and containing rocks and boulders. The latter support the burrow and serve as sunning and observation sites. Five dissected home-burrows showed no marked differences in general configuration. The yellow-bellied marmot (Marmota flaviventris) is a semi-fos- sorial rodent which spends up to 80% of its life in a burrow. Marmots are seasonally active above ground from early spring to fall (Armitage 1965). During this time they exhibit a bimodal pattern of daily activ- ity which peaks during the morning and again in late afternoon. Marmots retire to, the confines of the burrows during mid-day and at night. Subalpine populations of yellow-bellied marmots are character- ized by seasonal activity limited to about five months out of the year. The remainder of the year is spent in hibernation. Hibernation ac- counts for about 60% of the total underground existence of a marmot. In summer, if conditions of the present burrow are not suitable, a mar- mot can move or construct a new burrow. During winter, the marmot is hibernating and there is no way for it to control the environment in which it must survive. Hibernation burrows must be elected prior to onset of adverse environmental conditions and must provide the neces- sary requirements for survival. In summer the burrow also serves as a nursery, a haven from predators, and seclusion from interactions with other marmots. The quality of the burrow site is therefore a criti- cal aspect to be considered in the biology of the marmot. Marmot bur- row sites are usually located in open, herb-covered, talus slopes or grassy meadows in which rock outcrops and boulders are common 487(Svendsen in press). Rocks are used to burrow beneath, for lookouts, and in sunning. METHODS and STUDY AREA. Burrow sites of yellow-bellied marmots were studied in the vicinity of the Rocky Mountain Biological Laboratory (RMBL), 2900 m, Gothic, Gunnison County, Colorado.