than their American relatives, due to their necks being set differently. Compared to the American bison, the nose of the European bison is set further forward than the forehead when the neck is in a neutral position. The body of the wisent is less hairy, though its tail is hairier than that of the American species. The horns of the European bison point forward through the plane of their faces, making them more adept at fighting through the interlocking of horns in the same manner as domestic cattle, unlike the American bison, which favours charging. European bison are less tameable than the American ones, and breed with domestic cattle less readily. In terms of behavioural capability, European bison runs slower and with less stamina yet jumps higher and longer than American bisons, showing signs of more developed adaptations into mountainous habitats. Conservation The protection of the European bison has a long history; between the 15th and 18th centuries, those in the forest of Białowieża were protected and their diet supplemented. Efforts to restore this species to the wild began in 1929, with the establishment of the Bison Restitution Centre at Białowieża, Poland. Subsequently, in 1948, the Bison Breeding Centre was established within the Prioksko-Terrasny Biosphere Reserve. The modern herds are managed as two separate lines – one consisting of only Bison bonasus bonasus (all descended from only seven animals) and one consisting of all 12 ancestors, including the one B. b. caucasicus bull. The latter is generally not considered a separate subspecies because they contain DNA from both B. b. bonasus and B. b. caucasicius, although some scientists classify them as a new subspecies, B. b. montanus. Only a limited amount of inbreeding depression from the population bottleneck has been found, having a small effect on skeletal growth in cows and a small rise in calf mortality. Genetic variability continues to shrink. From five initial bulls, all current European bison bulls have one of only two remaining Y chromosomes. Reintroduction Beginning in 1951, European bison have been reintroduced into the wild, including some areas where they were never found wild. Free-ranging herds are currently found in Poland, Lithuania, Belarus, Ukraine, Bulgaria, Romania, Russia, Slovakia, Latvia, Switzerland, Kyrgyzstan, Germany, and in forest preserves in the Western Caucasus. The Białowieża Primeval Forest, an ancient woodland that straddles the border between Poland and Belarus, continues to have the largest free-living European bison population