NORTH AMERICA AND THE WEST INDIES 181 



ed if the species is to continue in the State. They put forth as 

 major causes in the decrease of the species the following facts : 

 (1) The fisher is by nature a solitary animal; (2) it requires a 

 large area of forage territory in order to live ; (3) the areas suit- 

 able for it are limited ; (4) the rate of reproduction is relatively 

 low; (5) the forests on which it depends are being constantly 

 reduced. To these factors may be added the hazard of forest 

 fires, and, finally, the fact that the gestation period is 11 

 months, so that trapping operations in winter, through de- 

 stroying pregnant females, inevitably double or triple the 

 potential loss of individuals. 



The beauty and rarity of fisher fur as well as the high price 

 it brings make it an attractive proposition for breeding under 

 artificial conditions. Ashbrook (1928) points out, however, 

 that the breeding of fishers in captivity for fur has not expanded 

 to any great extent since 1912, when there were but two fisher 

 "farms " on this continent. The difficulty seems to lie in getting 

 them to breed under these conditions even with seemingly 

 proper food. In the case of an animal naturally so shy and 

 nervous, breeding seems to be accomplished with difficulty 

 where there is the least disturbance. At present "little authen- 

 tic information is available on handling fishers in captivity," 

 but no doubt the difficulties will in time be solved. 



Dr. Francis Harper has contributed notes as to the number 

 of fisher pelts yielded in recent years. Thus in the London fur 

 market in 1927 one dealer offered 1,700 skins; at another sale 

 2,729 were offered (Journ. Soc. Preservation Fauna Emp., pt. 

 9, p. 75, 1929). According to Cameron (1936) the fur yield of 

 the Northwest Territories, Canada, included in 1934 the pelts 

 of 21 fishers. 



SHELL-HEAP MINK; "SEA MINK" 

 MUSTELA MACRODON (Prentiss) 



Lutreola macrodon Prentiss, Proc. U. S. Nat. Mus., vol. 26, p. 887, July 6, 1903 

 ("Brooklin, Hancock County, Maine," from Indian shell-heaps). 



SYNONYM: Lutreola vison antiquus Loomis, Amer. Journ. Sci., ser. 4, vol. 31, p. 228, 

 Mar., 1911 ("Flagg Island, Casco Bay, Maine"). 



FIGS.: Prentiss, 1903, fig. a (rostrum); Loomis, 1911, figs. 1, 2 (rostrum and jaws). 



Remains of a very large mink occur commonly in Indian 

 shell-heaps along the shores of the mainland and islands of the 

 coast of Maine, as independently described by Prentiss in 1903 



