Which is the tallest living land animal?

A bull giraffe can stand around five and a half metres, most of it neck and legs. The strange part is that the neck contains seven vertebrae, the same number as a human or a mouse, each simply enormously elongated, because that count is highly conserved across almost all mammals. Holding a head that high creates blood-pressure problems no other animal faces. The giraffe's heart is exceptionally thick-walled and generates roughly double the pressure of ours to push blood up to the brain, and the legs have tight skin and thick vessel walls to keep fluid from pooling in the feet. When the animal lowers its head to drink, a network of vessels at the base of the skull and valves in the neck arteries damp the surge that would otherwise follow. Height is useful for reaching acacia leaves other browsers cannot, and for spotting predators far across open country.

Male giraffes fight by swinging their necks and striking with their heads, a behaviour called necking.