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Giraffe
From Wikipedia, the free encyclopedia
Social
structure, reproduction and sexuality
Female giraffes associate
in groups of a dozen or so members, occasionally including a few younger males.
Males tend to live in "bachelor" herds, with older males often
leading solitary lives. Reproduction is polygamous, with a few older males
impregnating all the fertile females in a herd. Male giraffes determine female
fertility by tasting the female's urine in order to detect estrus, in a
multi-step process known as the flehmen response.
Giraffe gestation lasts
between 14 and 15 months, after which a single calf is born. The mother gives
birth standing up and the embryonic sack usually bursts when the baby falls to
the ground. Newborn giraffes are about 1.8 metres tall. Within a few hours of
being born, calves can run around and are indistinguishable from a week-old
calf; however, for the first two weeks, they spend most of their time lying
down, guarded by the mother. While adult giraffes are too large to be attacked
by most predators, the young can fall prey to lions, leopards, hyenas, and African
Wild Dogs. It has been speculated that their characteristic spotted pattern
provides a certain degree of camouflage. Only 25 to 50% of giraffe calves reach
adulthood; the life expectancy is between 20 and 25 years in the wild and 28
years in captivity.(Encyclopedia of Animals).
Chinese
painting of a giraffe brought by Admiral Zheng He and placed in a Ming Dynasty
zoo (AD 1414)
The males often engage in necking,
which has been described as having various functions. One of these is combat. These
battles can be fatal, but are more often less severe. The longer a neck is, and
the heavier the head at the end of the neck, the greater force a giraffe will
be able to deliver in a blow. It has also been observed that males that are
successful in necking have greater access to estrous females, so that the
length of the neck may be a product of sexual selection.[5]
Another function of necking
is affectionate and sexual, in which two males will caress and court each
other, leading up to mounting and climax. Same sex relations are more frequent
than heterosexual behavior. In one area 94% of mounting incidents were of a
homosexual nature. The proportion of same sex courtships varies between 30 and
75%, and at any given time one in twenty males will be engaged in affectionate
necking behavior with another male. Females, on the other hand, only appear to
have same sex relations in 1% of mounting incidents.[6]
Other
behavior
Giraffe,
Melbourne Zoo
The giraffe browses on the
twigs of trees, preferring trees of the genus Mimosa; but it appears
that it can live without inconvenience on other vegetable food. A giraffe can
eat 63 kg (140 lb) of leaves and twigs daily.
The pace of the giraffe is
an amble, though when pursued it can run extremely fast. It can not sustain a
lengthened chase. Its leg length compels an unusual gait with the left legs
moving together followed by right (similar to pacing) at low speed, and the
back legs crossing outside the front at high speed.
The giraffe defends itself
against threats by kicking with great force. A single well-placed kick of an
adult giraffe can shatter a lion's skull or break its spine.
The giraffe has one of the
shortest sleep requirements of any mammal, which is between 10 minutes and two
hours in a 24-hour period. This has led to the myth that giraffes cannot lie
down and that if they do so, they will die.
A giraffe will clean off
any bugs that appear on its face with its extremely long tongue (about 18 in/45
cm). The tongue is tough on account of the giraffe's diet, which includes
thorns from the tree it is making a meal. In Southern Africa, giraffes are
partial to all acacias — especially Acacia erioloba — and possess a
specially-adapted tongue and lips that appear to be immune to the vicious
thorns.
Giraffes are thought to be mute;
however, although generally quiet, they have been heard to grunt, snort and
bleat and also recent research has shown evidence that the animal communicates
at an infrasound level.[7]
The instinct of some other
African animals is to stay close to the giraffe, for the giraffe's high vantage
point can see predators from far away.[8]
Social
structure, reproduction and sexuality
Female giraffes associate
in groups of a dozen or so members, occasionally including a few younger males.
Males tend to live in "bachelor" herds, with older males often
leading solitary lives. Reproduction is polygamous, with a few older males
impregnating all the fertile females in a herd. Male giraffes determine female
fertility by tasting the female's urine in order to detect estrus, in a
multi-step process known as the flehmen response.
Giraffe gestation lasts
between 14 and 15 months, after which a single calf is born. The mother gives
birth standing up and the embryonic sack usually bursts when the baby falls to
the ground. Newborn giraffes are about 1.8 metres tall. Within a few hours of
being born, calves can run around and are indistinguishable from a week-old
calf; however, for the first two weeks, they spend most of their time lying
down, guarded by the mother. While adult giraffes are too large to be attacked
by most predators, the young can fall prey to lions, leopards, hyenas, and African
Wild Dogs. It has been speculated that their characteristic spotted pattern
provides a certain degree of camouflage. Only 25 to 50% of giraffe calves reach
adulthood; the life expectancy is between 20 and 25 years in the wild and 28
years in captivity.(Encyclopedia of Animals).
Chinese
painting of a giraffe brought by Admiral Zheng He and placed in a Ming Dynasty
zoo (AD 1414)
The males often engage in necking,
which has been described as having various functions. One of these is combat. These
battles can be fatal, but are more often less severe. The longer a neck is, and
the heavier the head at the end of the neck, the greater force a giraffe will
be able to deliver in a blow. It has also been observed that males that are
successful in necking have greater access to estrous females, so that the
length of the neck may be a product of sexual selection.[5]
Another function of necking
is affectionate and sexual, in which two males will caress and court each
other, leading up to mounting and climax. Same sex relations are more frequent
than heterosexual behavior. In one area 94% of mounting incidents were of a
homosexual nature. The proportion of same sex courtships varies between 30 and
75%, and at any given time one in twenty males will be engaged in affectionate
necking behavior with another male. Females, on the other hand, only appear to
have same sex relations in 1% of mounting incidents.[6]
Other
behavior
Giraffe,
Melbourne Zoo
The giraffe browses on the
twigs of trees, preferring trees of the genus Mimosa; but it appears
that it can live without inconvenience on other vegetable food. A giraffe can
eat 63 kg (140 lb) of leaves and twigs daily.
The pace of the giraffe is
an amble, though when pursued it can run extremely fast. It can not sustain a
lengthened chase. Its leg length compels an unusual gait with the left legs
moving together followed by right (similar to pacing) at low speed, and the
back legs crossing outside the front at high speed.
The giraffe defends itself
against threats by kicking with great force. A single well-placed kick of an
adult giraffe can shatter a lion's skull or break its spine.
The giraffe has one of the
shortest sleep requirements of any mammal, which is between 10 minutes and two
hours in a 24-hour period. This has led to the myth that giraffes cannot lie
down and that if they do so, they will die.
A giraffe will clean off
any bugs that appear on its face with its extremely long tongue (about 18 in/45
cm). The tongue is tough on account of the giraffe's diet, which includes
thorns from the tree it is making a meal. In Southern Africa, giraffes are
partial to all acacias — especially Acacia erioloba — and possess a
specially-adapted tongue and lips that appear to be immune to the vicious
thorns.
Giraffes are thought to be mute;
however, although generally quiet, they have been heard to grunt, snort and
bleat and also recent research has shown evidence that the animal communicates
at an infrasound level.[7]
The instinct of some other
African animals is to stay close to the giraffe, for the giraffe's high vantage
point can see predators from far away.[8]