The Savute Marsh area, 10 878 km² large, constitutes the western stretch of the park (50 km north of Mababe Gate). The Savuti Marsh is the relic of a large inland lake whose water supply was cut a long time ago by tectonic movements. Nowadays the marsh is fed by the erratic Savute Channel, which dries up when rainfall is abundant and floods up at other times. The channel can also stop flowing during long periods then curiously flows again, a consequence of tectonic activity in the area. As a result of this variable flow, there are hundred of dead trees along the channel's bank. The region is also covered with extensive savannahs and rolling grasslands, which makes wildlife particularly dynamic in this section of the park. At dry seasons, tourists going on safari often view warthogs, kudus, impalas, zebras, wildebeests and above all elephants bullying each other. At rain seasons, the rich birdlife of the park (450 species in the whole park) is well represented. Packs of lions, hyenas, zebras or more rarely cheetahs are visible as well. This region is indeed reputed for its annual migration of zebras and predators.