ORDER ARTIODACTYLA: EVEN -TOED UNGULATES 535 



have Caucasian blood. . . . The Berlin Zoo owned five pure 

 blooded wisents, In Hanover, Munich, Springe and Stellingen 

 there was 1 bull each." (Mohr, 1933, pp. 260-261.) A pure- 

 blooded wisent herd belonging to Herr von Beyme, at Scharbow 

 in Mecklenburg, developed foot-and-mouth disease and perished 

 in 1926. The loss of this herd resulted in the adoption of the 

 policy of "Verdrangungs-Zucht." 



In other parts of Europe. "The breeding efforts in Amsterdam 

 are of a somewhat recent date but look very promising. There 

 is one bull in Wien-Schoenbrunn and one in Budapest of which 

 the one in Hungary is used for cross breeding. It has thus far 

 been impossible to ascertain whether the animals that used to 

 be in Ascania Nova in South Russia are still alive. It seems as 

 if the cow of that region was sterile. The bulls of this breeding 

 place are used in the famous old 'supplantation breeding' (Ver- 

 drangungs-Zucht)." (Mohr, 1933, p. 261.) 



Breeding experiments. "Verdrangungs-Zucht (breeding by elimi- 

 nation) is as follows: Bison cows are bred to pureblood wisent bulls 

 and the resulting female calves brought in due time also to a wisent 

 bull and so on, while the male calves are excluded from breeding. 

 Experience shows that by continuing this process long enough, even 

 at the end of 10 generations the descendants can scarcely be dis- 

 tinguished from pure stock wisents. ... To Springe all the avail- 

 able pure-blooded wisents have been brought and are said to be doing 

 well. In the meantime a large new reserve has been created in the 

 Schorfheide, a very extensive forest in the Uckermark. ... There 

 are here a pure-blooded wisent bull and quite a number of hybrid 

 cows, and the above discussed Verdrangungszucht is to be con- 

 tinued, there being in all 29 animals here." (Theodor G. Ahrens, 

 MS., October, 1935.) 



A new Wisent park, with a stock of 6 animals, was to be opened 

 in connection with the Hellabrunn Zoo, near Munich, in 1936. 



Similar breeding experiments are being undertaken by the Polish 

 Forest Administration at a new Wisent enclosure in the Forestry 

 District of Ksionsch on the Pilica River southwest of Warsaw. "All 

 the halfbreed cows in Bialowies will be brought here and bred to a 

 pureblooded bull, while in Bialowies, in the future, only pure- 

 blooded animals will be tolerated." (Theodor G. Ahrens, MS., 

 October, 1935.) A further step contemplated is the segregation of 

 the pure Lithuanian stock (B. b. bonasus) at Bialowies and the 

 provision of a place for the Caucasus-blooded line (B. b. caucasicus) 

 in the Tatra (Mohr, 1934). 



Rate of increase. The feral Wisent cow keeps her calf with her 

 about three years and does not rut during this time. For a more 

 rapid increase, 30-40 cows of the Bialowies herd were kept in a 



