The giraffe is an unusual animal that contains an interesting design mechanism. Did you know that a full grown giraffe's heart weighs over 24 pounds and pumps 16 gallons a minute? Because the giraffe's heart is much larger than his head, a series of special one-way, back-flow preventer valves are needed in the neck to regulate the flow of blood to the head, especially when the giraffe is bending down to get that much needed drink of water. Without these valves, the immense blood pressure coupled with gravity would make for one nasty headache and other such repercussions. Elastic blood vessels in the giraffe's head allow harboring of enough blood to prevent the giraffe from passing out when bent in this position.
The creationist points out that this intricate design mechanism is, you guessed it, a design! The evolutionist will have you believe that this system evolved with time, that eventually a giraffe mutated merrily along until the valves properly formed in the neck and the elastic blood vessels sufficiently formed in the head (along with other details left out here).
If evolution is true, the struggle for the Giraffe to survive must have been one ugly sight! Let's take a look at one possible outcome...