Plains zebra & blue wildebeest

One of the strange things we notice on the Serengeti was that most of the herds of wildebeest appeared to be led by zebra stallions. We were told by our guide that the lone stallions (usually young males who have not yet managed to take over a 'harem' of females) benefit from this relationship through reduced chance of predation - 'safety in numbers', & the wildebeest gain the benefit of the much sharper eyes of the zebra spotting danger more quickly. On this occasion however, the zebra failed to spot a lioness watching the herd from a tree http://www.projectnoah.org/spottings/7077319 & we witnessed her hunt & kill one of the wildebeest.