







paratively scarce. 



THE BEAVER FAMILY 



{Castoridcc) 



EAVERS have been placed in a family by themselves, because of certain 

 well-known, distinctive features. Not only are their outward habits 

 peculiar, but their anatomical markings are distinct. Rodents of this type 

 are characterized by a massive skull. There are no postorbial processes. 

 The cheek teeth are rootless, and on each side there are one premolar above 

 and one below. The tail is broad and spatulate, and the hind feet webbed, to 

 assist in swimming. Beavers are aquatic in habit, building their homes in the 

 dams which they themselves have constructed. In this and in other work 

 they display engineering skill of a high order. Economically also they are 

 important. A very valuable trade in Beaver skins was carried on during the 

 early days of this country, which continued until the animals became com- 



BEAVER 

 Castor canadensis ( Kuhl) 



General Description. — Much the largest of Amer- 

 ican rodents, weighing up to 50 pounds. Head broad 

 and rounded ; nose bknit ; incisors prominent and of a 

 deep orange color; ears quite short and not projecting 

 much above long hair of head; body very thick set 

 and heavy ; tail broad and spatulate, flattened horizon- 

 tally, and, about one-half length of head and body; 

 legs short ; toes five on each foot ; hind feet webbed 

 and with claw of second toe double or divided; musk 

 secreting anal glands ; general color deep dark chest- 

 nut ; paler below ; pelage composed of dense short 

 underfur and sparser outer fur of longer, harder hairs. 

 Aquatic in habit. 



Dental Formula.- 



Incisors. i-~' ; Canines, "^^ : 



Pre- 



molars. ^ — ^ ; Molars, ;?-^^20. 

 I— I ' 3—3 



Pelage. — Adults : Sexes identical. Seasonal varia- 

 tion present but not especially conspicuous. General 

 color brown to blackish-brown ; hairs on uppei" parts 

 dark brown at base, tipped with lighter brown or chest- 

 nut ; underparts paler than back; sides of neck and 

 rump light cinnamon brown ; ears black ; tail blackish- 

 brown. VouNX.: Lighter than adults. 



Measurements. — Total length about 42 inches ; tail 

 16 inches long by 4.5 inches wide ; hind foot, 7 inches. 



Range. — From latitude 40° northward to Labrador 



and Hudson Bay region, and in western portion of 

 range to the Arctic circle west to Cascade Mountains. 



Food. — Twigs and bark of many trees, but principally 

 bark of poplar and willow. 



Remarks. — This highly specialized animal is placed 

 in a family by itself, generally intermediate between 

 Squirrels and the Rats and Mice. The Beaver may 

 be easily known by its large size and peculiar tail. 

 Variations in color, while not especially conspicuous, 

 together with cranial characters and dififerences in 

 size have resulted in some seven species and subspecies 

 being formed. 



Related Species 



Canada Beaver. — Castor canadensis canadensis Kuhl. 

 Typical animal as described above. Northeastern North 

 America, or northern tree limit, to United States, and 

 west to Cascade Mountains. 



Sonora Beaver, or Broad-tailed Beaver. — Castor 

 canadensis frondator Mearns. Larger than Canada 

 Beaver. Paler and with broader tail. Southward from 

 Montana and Wyoming to Mexico along wooded 

 streams. 



Pacific Beaver. — Castor canadensis pacificus 

 Rhoads. Largest of the Beavers. Tail long; color 

 reddish-chestnut. Pacific slope, California to Alaska. 



In the days of the early settlement of America 

 the Beaver, including its races, was fotind from 

 the Atlantic to the Pacific, and from the limit of 

 trees in the far north of Canada to the Gulf of 

 Mexico, wherever conditions were favorable. 

 Today, however, thanks to the unstinted greed 

 of man, this harmless animal has disappeared 



from the greater part of its former range, and 

 over mtich of the remainder it is rare. 



Within the last twenty years nature lovers and 

 the better class of sportsmen have realized the 

 great loss to the country which would result 

 from the extinction of this valuable animal, and 

 have succeeded in having it protected in many 



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