Yes, as children, we all thought that giraffes had long necks so they could eat the most tender leaves from the tops of trees with ease. But, as with many things, the truth may have more to do with power and sex.
Giraffes do eat from tall plants, but not often. During the dry season, when competition for food should be fiercest and eating from the top down should be an advantage, they eat from low shrubs. Female giraffes spend most of their time feeding with their necks horizontal. And both sexes feed faster and more often with their necks bent.
Also, if giraffe necks evolved for feeding, why haven’t their legs evolved to be longer instead? (Physiologically speaking, top-heavy things don’t make a lot of sense.)
Instead, scientists have suggested that “increased neck length has a sexually selected origin.”
Males fight for dominance and access to females in a unique way: by clubbing opponents with well-armored heads on long necks. Injury and death during intrasexual combat is not uncommon, and larger-necked males are dominant and gain the greatest access to estrous females. Males’ necks and skulls are not only larger and more armored than those of females’ (which do not fight), but they also continue growing with age.
There you have it. Bear in mind that this could be a more exciting way to teach children about natural selection and “the birds and the bees” than resorting to birds or bees or Mendel’s peas.