NORTH AMERICA AND THE WEST INDIES 75 



and richness of color. They are decidedly superior to the 

 Canadian and Alaskan skins . . . For many years the 

 beavers of the region south of Lake Superior have been care- 

 fully protected . . . They are now fairly abundant in the 

 region. " 



MISSOURI BASIN BEAVER 



CASTOR CANADENSIS MISSOURIENSIS Bailey 



Castor canadensis missouriensis Bailey, Journ. Mammalogy, vol. 1, p. 32, Nov. 28, 

 1919 ("Apple Creek, 7 miles east of Bismarck, North Dakota"). 



This race is said to be "slightly smaller than canadensis and 

 much paler and duller brown. Skull more triangular in outline, 

 not so massive and heavy ; much like that of mexicanus, shorter 

 and heavier than that offrondator. From mexicanus the colors 

 differ in being noticeably duller and darker; from frondator, 

 duller, and not so rusty. " The total length of the type (prob- 

 ably not fully grown) was 900 mm. "Specimens show closer 

 affinity with those of the Rio Grande drainage, than with those 

 in the same State [North Dakota] in the streams flowing into 

 Hudson Bay." 



The range of this form of beaver is believed to be the drain- 

 age system of the Missouri River, typically in western North 

 Dakota, but further study is needed to settle this. Provision- 

 ally, South Dakota, Nebraska, and possibly Kansas may be 

 included in its present or former range. Vernon Bailey (1926) 

 has given an excellent account of the recent status of the beaver 

 in North Dakota. He writes that in 1804-5, Lewis and Clark 

 found beavers abundant along the Missouri, even near long- 

 established Indian settlements. At that time trappers were 

 just beginning to find the region a source of pelts, and in the 

 three decades following they reaped a large harvest. In 1833 

 Maximilian reported that 25,000 beaver skins had been bought 

 during the year at Fort Union (now Buford); by the next 

 decade, however, Audubon found them already scarce. Never- 

 theless, Bailey writes, where "the beavers had the protection 

 of the deep water and high banks of the larger rivers" they 

 persisted and "with characteristic tenacity they still cling to 

 their old haunts or merely scatter out to establish new colonies 

 in tributary streams." As late as 1913, he and others found 

 small numbers as at Buford, Fort Clark, and near Williston. 

 At this time also they were present on the Little Missouri and 



