Friday, 25 June 2010

The World´s Tallest Land Mammal

Giraffes are renowned as the tallest land mammals, thanks to their very tall legs and long necks. Male giraffes can grow up to 5.5 meters (18 ft) and females can reach 4 to 4.5 meters (13 to 14.8 ft). This height, allied with keen eyesight, helps the giraffe to keep a sharp outlook for the approach of predators across the wide region of the African savanna. Unfortunately, the spectacular height of the giraffe can be a disadvantage as well – it is difficult and dangerous for a giraffe to drink at a water hole. To do so they must stretch their legs and bend down in an uncomfortable position, making them defenseless to predators.

A giraffe´s long neck is made up, like that of a man and most other mammals, of only 7 vertebrae. Male giraffes sometimes battle one another by striking their long necks and heads against each other, in a process known as necking. The heavy hard heads of the male giraffes makes an excellent hammer-like weapon when swung around by the long neck. Both sexes have short, skin-covered horns, although the horns of the female are smaller. A giraffe has a massive heart, which can weigh about 10 kg (22 lb). The heart must pump at a pressure 2 to 3 times that of a healthy man, though by the time the blood reaches the brain, the pressure has been reduced by the gravity. When the giraffe lowers its head to drink, it dips 7 feet below the heart, and this could cause a dangerous rush of blood to the brain. Precisely why such a dangerous rush of blood does not take place is not clear.

Giraffes are timid and inoffensive towards other animals. On average these fascinating creatures roam the open grasslands in small groups of a dozen or so members. Mating can occur at any time of the year, with a few older males impregnating all the fertile females in a herd. Male’s test the females like any other hoofed animals, approaching and nudging them until they respond by urinating. To determine the female giraffe´s fertility, the male smells and tastes the urine in order to detect estrus (a multi-step procedure known as the Flehmen response). Calves are born after a gestation period of about 400 to 460 days. The mothers give birth standing up. Their young undergo a rather impolite welcome into the world by falling more than 1.5 meters (5 ft) to the ground at birth. Within a few hours, calves are capable of running with their mothers. However, during the first two weeks they usually spend their time lying down, guarded by the mother.

Giraffes will eat from a variety of trees, though acacias are a favorite. These guys have quite an interesting way of eating. Just like goats and cows, giraffes are also ruminants, which mean that they have four-chambered stomachs. They regurgitate semi-digested food, mix it with saliva again, and chew each wad of cud several times, at a rate of 1 chew per second.

Giraffes have spectacular spotted coats. Each giraffe has its own unique spot pattern in its coat, very much like our unique finger prints. Unfortunately these amazing creatures are hunted for their hides, tails and meat. For instance, giraffe skin is used as drums, watertight bowls and even shoes. The tails are used as good luck charms, thread and flyswatters. Some people believe that the hair on giraffe coats can induce fertility. In addition habitat destruction has also been a threat to the giraffe. The giraffe population is diminishing in West Africa. On the other hand, they are stable in eastern and southern Africa due to the ranches and sanctuaries. The giraffe is a protected species in most of its range.

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