Giraffes are the tallest land animals on the planet, ranging in height from 13 to 19 feet. Mature female giraffes can reach up to 1,500 pounds and males tip the scales at 3,000 pounds. Even at birth, calves are already 6 feet tall and 150 pounds. To accommodate their unusual proportions, dizzying height and tremendous weight, the internal anatomy of the giraffe must be highly specialized.
The most outstanding feature of the giraffe is its neck. The giraffe's neck is 6 feet long and contains approximately 550 pounds of muscle, and yet it has only seven vertebrae -- the same number of vertebrae as the human neck. However, the vertebrae are elongated, well-spaced and supported by very flexible joints. Upward-projecting spines are situated at the base of the neck, which serve to support the heavy muscles and hold the neck upright.
Mouth and Tongue
According to the Giraffe Conservation Foundation, the giraffe's tongue and mouth structure are specifically adapted to its diet. Giraffes consume various types of vegetation, but it's particularly partial to the thorny acacia tree. Its 18- to 20-inch-long prehensile tongue and grooved upper palate are designed to grasp and strip leaves from branches. A giraffe uses its tongue to sort the leaves from the thorns. The animal's tongue and mouth are protected from the sharp thorns by thick papillae and viscous saliva.
Heart and Circulation
The giraffe's blood pressure is twice that of humans -- a necessity to push blood up the neck to its brain. According to BBC Earth News, it was previously believed that the high pressure originated from a large heart. However, a study conducted at the Centre for Veterinary Wildlife Studies at the University of Pretoria South Africa revealed that the giraffe's heart is relatively small, and that its extraordinary power is the result of thick walls and a small radius. The heart is supported by a self-regulating cardiovascular system. Pressure sensors along blood vessels signal constriction and expansion to adjust blood flow, as does a muscular cuff that encircles the jugular vein.
Nestled within the giraffe's long neck is a 12-foot trachea. When the giraffe inhales fresh air, it's impossible for it to fully expel the previous breath, resulting in oxygen-depleted air being trapped in the trachea. The giraffe compensates for this problem with a slow respiratory rate and oversized lungs. The giraffe's respiratory rate is one-third that of humans, and its lungs are eight times as large. The slow exchange of air and the large volume of it retained in the lungs balance the oxygen and carbon dioxide ratio and prevent trachea damage.
- BBC Earth News: 'Supercharged' Heart Pumps Blood Up a Giraffe's Neck
- Animalphiles: Giraffe Physiology Mystery Solved
- The Science Creative Quarterly: The Giraffe: A Favorite Textbook Illustration of Evolutionary Theories
- Animal Corner: Giraffes
- Animal Corner: Giraffe Anatomy
- Giraffe Conservation Foundation: Giraffe - The Facts
- Anup Shah/Photodisc/Getty Images