PLANET EARTH Great Plains

Only fat healthy cubs will survive the Arctic winter. The vast majority of the goslings are still flourishing. Their parents lead them down to the safety of the water as soon as they're strong enough to make the journey. For the foxes boom time has come to an end but the mother has given her cubs the best possible start in life. The geese will continue grazing the tundra until the summer ends, and they're forced to head south for the winter.



At these latitudes the Sun's rays are week and grass can only grow here for a few months a year but further south summers are longer and the grasslands flourish. The prairies of North America. This rich pasture once supported the greatest herds ever seen on our planet. There were once sixty million bison but no animal is immune to intensive hunting by man or the destruction of its habitat and a century ago the bison（野牛） were reduced to barely a thousand.



Now, thanks to rigorous protection, the species is recovering. The growing season is long and the grass here can support herds all year around. Male bison weigh in at one ton. In high summer the bulls are fat from the rich grazing and in prime condition but only a few will mate. Exactly which few is about to be decided.