A beautiful animal…
…and one that perfectly illustrates the principle of creation by design!
"Since the giraffe has such a large neck, it has a very large and powerful heart to pump the blood to the brain. Theoretically, the immense pressure of the blood pumped by this massive heart would rupture blood vessels in the brain if the giraffe moved its head downward! In reality, however, the giraffe is able to execute such an action with no damage at all. The way in which it does this is amazing…
Valves in the arteries of the neck close whenever the giraffe bends its head down, limiting the flow of blood to the brain. The blood that is not stopped goes into the “rete mirabile,” a sponge-like cluster of vessels under the brain. Since the brain receives the blood indirectly from the rete mirabile, it is not damaged by any high pressures. When the giraffe lifts its head up, the valves open and the rete mirabile brings more blood to the brain. In addition, some valves in the neck veins close to equalize the blood pressure. This prevents the giraffe from fainting from lack of oxygen when it gets up!
When we look at this whole system we immediately see that any defect or incompleteness in it would result in serious consequences for the giraffe. It could never have evolved gradually over billions of years! Indeed, only God could create something this wonderful." (Michale Denk)