The giraffe has the highest blood pressure of any living land animal, partly because of its long neck.
A giraffe’s heart must generate enough pressure to push blood upward to the brain, several metres above the ground. Its heart is large and muscular, and its thick blood vessels and specialized valves help control circulation. When the animal lowers its head to drink, additional mechanisms help prevent excessive pressure reaching the brain.
Giraffes also have a dense network of vessels near the brain called the rete mirabile. This network can help regulate blood flow during rapid changes in head position. Their lower-leg tissues are adapted to withstand high hydrostatic pressure as blood moves downward.
The giraffe is the tallest living terrestrial animal. Its long neck contains seven cervical vertebrae, the same basic number found in most mammals, but each vertebra is greatly elongated. Giraffes browse mainly on leaves, especially from acacia and related trees.