Wildebeeste, again.

Just about every time I turn on the TV these days, there is a huge herd of wildebeeste massing on the steep bank of a great river. They know they need to cross to get to new grazing lands, but they are frightened of the crocodiles in the river. Eventually the pressure of the herd behind is too great, and they plunge in. Inevitably some are dragged under, drowned and devoured by the crocodiles. Sometimes the zebras go along with the wildebeestes, taking advantage of their bulk for some protection from the crocodiles. This is all very interesting.

But why is it on every channel, all the time?