THE AMPHIBIA AND REPTILIA OF COLORADO 

 PART I 1 



By Max M. Ellis and Junius Henderson 



Comparatively little has been published concerning the reptiles 

 and amphibians of Colorado. The limited literature consists of 

 records of species scattered through a number of publications, some 

 of which are inaccessible to the general public. Considerable unre- 

 corded material having accumulated, it seems opportune to publish 

 this present report in order to place in the hands of naturalists and the 

 general public such information as we have, bringing together into 

 compact form the records heretofore published, and adding to them 

 the unpublished material, so far as the same has come to our attention. 



Environmental Conditions. — Colorado has an area of about 103,500 

 square miles, a latitudinal extent of about 276 miles and a longitudinal 

 extent of about 375 miles. It is traversed from north to south, 

 irregularly, by the continental divide — the "backbone of the conti- 

 nent" — its waters draining into two oceans. Its rock formations 

 represent all the geological systems except possibly the Silurian. 

 Though its average altitude is only approximately 6,800 feet, it varies 

 in altitude from less than 3,500 feet to over 14,000 feet above sea- 

 level, with consequent differences in climatic and other environmental 

 conditions. 2 The mean annual rainfall varies in a general way with 

 altitude and topography, from less than 10 inches to 30 inches or more. 

 Data as to temperatures in the larger and higher masses of mountains 

 are as yet very meager, but it may be said that the temperature at 

 elevations of from 13,000 to 14,000 feet drops to a point below freezing 

 nightly even in summer time, while the mean temperature for the 

 warmest months in some of the lower portions of the state is nearly 

 eighty degrees. On the whole, the state is a cool one. The diurnal 

 range of temperature is great over the entire state. 



1 Publication of the Colorado Biological Survey, No. 14. 



•Robbins, W. W., "Climatology and Vegetation in Colorado," Botanical Gazelle, Vol. XLIX, pp. 

 256-280, iqio, with maps, diagrams, tables and general discussion. 



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