Giraffe have unusually high heart rates for their size, at 150 beats per minute. When the animal lowers its head the blood rushes down fairly unopposed and a rete mirabile in the upper neck, with its large cross sectional area, prevents excess blood flow to the brain. When it raises again, the blood vessels constrict and direct blood into the brain so the animal does not faint. The jugular veins contain several (most commonly seven) valves to prevent blood flowing back into the head from the inferior vena cava and right atrium while the head is lowered. Conversely, the blood vessels
Martian (The War of the Worlds) Martian (The War of the Worlds) Little about the Martians is definitive, the story being told by a first-person narrator. The Martians are described as octopus-like creatures: the "body" consisting of a disembodied head nearly across, having two eyes; a v-shaped, beak-like mouth; and two branches each of eight 'almost whip-like' tentacles, grouped around the mouth, referred to as the 'hands'. They reproduce asexually, by "budding" off from a parent. Internally, the Martians consist of a brain, lungs, heart, and blood vessels; they have no organs for digestion, and therefore sustain themselves on Earth by mechanically transfusing blood via pipettes