Giraffes are the tallest land based mammal at 18 feet for males and 15 feet for females. Their necks are 6 feet tall and weigh 600 pounds. Giraffes are well adapted for living in tree-dotted African plains, as their necks allow them to reach tall trees for food. However, Giraffes have not always had this unique stature and iconic neck. 

Many researchers believe that instead of the elongation of the giraffes neck being a result of natural selection to compete for food, it was sexual selection to compete for mates. This idea was another major contribution of Charles Darwin to the field of evolutionary thought, but he never applied it to the Giraffes neck. Researchers argued that although giraffes necks allow them to reach for food high in trees, they often browse low shrubs more often and can even feed faster by doing so.  Most importantly, giraffes frequently use their necks to wack other males in a competition for mates. Some researchers believe that it was this competition for mates that, over millions of years, had driven their ancestors toward ever-longing necks.  

Climate change is already changing environments around the world and affecting its wildlife and the African savanna is not immune to these changes. While giraffes used to roam the entirety of the African savanna, they are now clumped in areas of the continent. Through drought,  deforestation, and illegal poaching, a silent extinction of giraffes has occurred. I can speculate that with their little need for water and sleep, giraffes will continue to travel in herds where trees and bushes are more abundant. Thankfully they have their long necks that allow them to have a wider variety of food sources, from shrubs to tall trees, to fulfill their 75 pounds a day of dietary needs.