Giraffes are very unique animals. They are the tallest of mammals, they have the largest heart in proportion to their body size to be able to pump blood into their brain and they has special valves used to manage the high pressure at which their blood is pumped throughout their bodies. They are the most liberal of mammals in their social organisation with no evident leaders. Baby giraffes live in creches where one mother giraffe takes care of all the babies while other mothers go to browse. Still scientists debate whether giraffes grew their long necks to reach out for highly nutritious plants or if this happened to be able to reach the ground to drink water. A discussion similar to that of the chicken and the egg.