Natural History:
The giraffe is the tallest living animal, and
its neck the longest among living species. Nevertheless, it has (like all
mammals) only seven cervical (neck) vertebrate.
Giraffes are shy plant-eating creatures that stay
in herds of up to ten animals. They are capable of feeding on a variety of
plant matter, including mimosa, apricot, and other trees.
Perhaps the most intriguing aspect of giraffe
biology is their circulatory physiology. For example, when a giraffe
lowers its head to drink from a pond, the flow of blood should cause the
brain to explode, while raising the head should result in the giraffe
passing out. Of course, neither action happens, in part because of the
large strong heart that produces a blood pressure twice that seen in
humans, and in part because the neck vessels are equipped with numerous
valves that help regulate blood pressure under different conditions.
