This modern and large enclosed animal park around 4km west of Palace Park is your best chance to see an actual bison. Though the bison died out in the wild in 1919, it's been successfully reintroduced here and elsewhere in the park. The reserve holds several other species in large cages or pens that are typical of the puszcza, including elk, wild boar, wolves and roe deer.
Another peculiarity is the tarpan (Equus caballus gomelini), a small, stumpy, mouse-coloured horse with a dark stripe running along its back from head to tail. The tarpan is related to the wild horse (E ferus silvestris) that once populated the Ukrainian steppes but became extinct in the 19th century. Like many things in Poland, it has a past tangled in history: before and during WWII, the Nazis bred the tarpans to create a sort of throwback Aryan horse. Hermann Göring had wanted Białowieża to be a Nazi hunting lodge filled with mythical creatures.
The reserve also has żubroń, a cross between a bison and cow, which has been bred at Białowieża to be even larger than the bison, reaching up to 1200kg.
The reserve is off the Hajnówka road, Hwy 689. By foot or bike, take the green- or yellow-marked trails, both starting from the PTTK office, or the trail called Żebra Żubra (Bison's Ribs).