Giraffe
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Scientific classification |
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Binomial name |
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Giraffa camelopardalis |
The giraffe (Giraffa
camelopardalis) is an African even-toed ungulate mammal, the tallest of all
land-living animal species. Males can be 4.8 to 5.5 metres (16 to 18 feet) tall
and weigh up to 1,360 kilograms (3,000 pounds). The record-sized bull was 5.87
m (19.2 feet) tall and weighed approximately 2,000 kg (4,400 lbs.). [2] Females are generally slightly shorter and weigh less
than the males do.
The giraffe is related to deer
and cattle, but is placed in a separate family, the Giraffidae, consisting only
of the giraffe and its closest relative, the okapi. Its range extends from Chad
to South Africa.
The species name camelopardalis
(camelopard) is derived from its early Roman name, where it was described as
having characteristics of both a camel and a leopard .[3]
The English word camelopard first appeared in the 14th century, and
survived in common usage well into the 19th century. A number of European
languages retain it. The Arabic word الزرافة ziraafa or zurapha, meaning "assemblage" (of animals), or
just "tall", was used in English from the sixteenth century on, often
in the Italianate form giraffa.
Giraffes
use their long, prehensile tongues to extend their reach. Specimen at the National
Museum of Natural History, Washington, DC.
Male giraffes are around
16–18 feet tall at the horn tips, and weigh 1700–4200 lb. Females are one to
two feet shorter and weigh several hundred pounds less than males. Both sexes
have horns, although the horns of a female are smaller. The prominent horns are
formed from ossified cartilage and are called ossicones. Males sometimes
develop calcium deposits which form bumps on their skull as they age, which can
give the appearance of up to three further horns.[4]
Giraffes have spots
covering their entire bodies, except their underbellies, with each giraffe
having a unique pattern of spots. They have long, prehensile tongues that are
distinctly blue-black to protect from sunburn. Giraffes have long necks, which
they use to browse the leaves of trees. They possess seven vertebrae in the
neck (the usual number for a mammal). They also have slightly elongated
forelegs, about 10% longer than their hind legs.
Modifications to the
giraffe's structure have evolved, particularly to the circulatory system. A
giraffe's heart, which can weigh up to 10 kg (24 lb) and about 2 feet
long, has to generate around double the normal blood pressure for an average
large mammal in order to maintain blood flow to the brain against gravity. In
the upper neck, a complex pressure-regulation system called the rete mirabile
prevents excess blood flow to the brain when the giraffe lowers its head to
drink. Conversely, the blood vessels in the lower legs are under great pressure
(because of the weight of fluid pressing down on them). In other animals such
pressure would force the blood out through the capillary walls; giraffes,
however, have a very tight sheath of thick skin over their lower limbs which
maintains high extravascular pressure in exactly the same way as a pilot's g-suit.
Some giraffes can lose the
bottom part of their tail to cysts resulting from tick bites.