two adult giraffes walking with one smaller baby giraffe on a grassy plain
A new study questions the decades-long theory about why giraffes have such long necks.
  • Giraffes have the longest necks of any living animal but scientists can't agree on why. 
  • Scientists largely agree that males drove the evolution of long necks to compete for mates.
  • But a new study offers clues to the contrary, challenging the leading "necks for sex" theory.

Giraffes didn't always look like the elegant giants we recognize — ancient giraffes looked more like deer. But something happened over the past millennia that drove giraffes to evolve the longest necks of any living animal.