Giraffa is a genus of big mammals which
members are commonly known as giraffes. The number of species in this genus is an
open debate in the scientific community. There are four different lines of though:
each line affirms that the genus is formed eaither by one, three, four or eight species. However, all of them agree that giraffes are animals with very particular characteristics that make them unique. If you want to
learn more about this amazing genus of animals, join me during this article.
One of the
most outstanding characteristics of giraffes is their huge size. In fact,
they are the tallest land animals on the planet. They can reach heights ranging from 14.1 to 18.7 ft (4.3 and 5.7 m). The tallest giraffe ever recorded was 19.3 ft
(5.88 m) tall. Their weight is not negligible either, these animals can get
quite heavy. Males are heavier than females, with an average weight of 2,268 lb (1,192 kg)
and females are slightly lighter, with an average weight of 1,825 lb (828 kg).
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| David Davies https://creativecommons.org/licenses/by-sa/2.0/ |
Although their
size is amazing, they have other interesting characteristics on their anatomy,
for example, their skull. From the outside, two horn-looking structures called
ossicons project from the top of their head. These are highly vascularized,
which has led biologists to believe that they may play a role in thermoregulation.
They are also used as weapons during combats between males. During their life,
giraffes form calcium deposits to make the skull more resistant against bumps
during combat. The skulls of giraffes are lightened by sinuses but, in the case
of males, those sinuses fill up during their life, turning heavier as the male
gets older. This is useful to hit harder when fighting for mating.
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| Photo by: David Davies https://creativecommons.org/licenses/by-sa/2.0/ |
If there is
one characteristic about giraffes that defines them the most, it is their neck.
It is extremely elongated, reaching a length between 6.6 and 7.9 ft (2 and 2.4
m), making it up to almost half of their height. Their neck is that long thanks
to elongated cervical vertebrae, which can be 11 in (28 cm) each. Its length requires some special features in its structure to be able to hold it up. It contains
strong cervical muscles and a strengthened nuchal ligament, both attached to
dorsal spines in the vertebrae. Most of the growth of the neck takes place
after birth, as it would be impossible to give birth to long-necked cubs.
There are a
few different evolutionary theories for the unusual length of their neck. The oldest
one, first proposed by Darwin, says that the goal of their long neck is related
to their feeding habits. A long neck lets them avoid competence against other
animals at a lower height when eating from trees. However, it has been recently
denied by scientists because the time that giraffes spend eating at high parts
of trees is not significant enough. Also, some studies say that giraffes with
long necks are more likely to die during drought periods, due to the high
nutrient requirements of long necks.
Another theory
says that the long neck is linked to sexual selection, as it would give an advantage
in combat between males for mating. Male giraffes use their muscular necks and
heavy heads to hit other males while fighting. This theory is not widely accepted
because it does not explain long necks in female giraffes.
One last theory I would like to mention is that long necks provide higher vigilance,
allowing giraffes to cover bigger areas. There is not a unified consensus about this theory and it is still being debated in the scientific community.
Giraffes have
an extraordinary anatomy with amazing features. The mysterious evolutionary origins
of these characteristics make them really interesting subjects of study for
scientists.
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