Male giraffes have a very unusual way of finding a mate, as this video animates. They don't use extravagant displays or special vocalizations to attract the attention of females. Instead, they just follow female giraffes around, bumping against them strategically, trying to get a whiff of female giraffe urine.
It seems that the males can figure out whether the females are ovulating based on the smell, and possibly, a little taste of the yellow stuff. And if the female is indeed ready to reproduce, that's pretty much all it takes for the male to make his move, which basically means just waiting for his lady to stand still long enough for copulation to occur. The female also has to bear the weight of the male, who can be one and a half times bigger!