The name of two species of wild oxen, the European bison or wisent and the American bison or buffalo. Only a small number of European bison now exist, bred from zoo specimens, and in a protected state in forest of Lithuania. Two further species, now extinct, inhabited Europe and Great Britain for much of the Quaternary period. The great steppe wisent was present during both interglacials and cold period. The smaller wood wisent, was only present in Europe during interglacials. Sometimes these animals are called aurochs. In North America, a number of species preceded today's bison. One species, popularly called 'buffalo', formerly roamed in vast herds over the interior of the continent, mainly in the Rocky Mountains.