When it comes to giraffes, their long necks are their distinctive feature.
They are also the tallest animals in the world because of their long necks. They must have a great view all the time.
There is still a secret about giraffes that many people don’t know about. Let’s explore the secret of giraffes together.

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～ Basic information. ～

Artiodactyla－Giraffidae－Giraffe genus.

Male length4.7～5.3m weight:800～1930㎏.
Female length3.9～4.5m weight550～1180㎏.

Male giraffes are already tall on average, but the Guinness record is held by a 5.7m giraffe kept in Australia.

Giraffes live in about nine different regions across Africa.
I will introduce some of the countries in these wide regions.

Central Africa.:Chad, Niger, Cameroon, Democratic Republic of the Congo.
Eastern Africa.:Ethiopia, Somalia, Tanzania, Kenya, Uganda, Sudan.
Southern Africa.:Namibia, Botswana, South Africa.

You can see that giraffes live in many countries.

Giraffes mainly eat leaves, young leaves, and small branches of acacia and mimosaceae trees using their 45cm long tongue.
They also eat grass growing on the ground, but it looks a little difficult to eat as they open their front legs.

Giraffes are social animals that form groups consisting of several to dozens of individuals centered around the male leader.
The largest group is said to have consisted of 70 individuals.

Female giraffes tend to stay in the group they were born into, but male giraffes leave to find a group where they can become the leader.

Giraffes fight using their long necks, called “necking,” to hit each other when mating with females.
The fight creates a hierarchy among males, and the higher the rank, the more priority they have in mating with females.
Some giraffes are injured by this necking, so it is clear that it is powerful.

Giraffe females give birth about 450 days after becoming pregnant.
When giving birth, they stand because they do not know when they will be targeted by enemies.
Giraffes’ legs are about 2m long, so babies are born from that height.
The size of the newborn baby is about 1.7-2m, which is about the same height as a tall man.

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Giraffe’s Q&A.

Why do giraffes have long necks?

When it comes to giraffes, you might wonder why their necks are so long.

There are two common answers to this question.

1）It stretched its neck to eat leaves from high places.
2）A giraffe with a long neck was born due to a mutation and survived.
Which answer is correct?

Actually, the reason why giraffes have long necks has not been clarified.
There are several theories, so we cannot clearly tell you which answer is correct.
We hope that it will be clarified in future research.

Do giraffes and humans have different numbers of neck bones?

Giraffes and humans are both mammals, so the number of bones in their necks is fixed at seven.
Although the number of bones is the same, there is a difference in the length of each bone, with giraffes having longer bones than humans.

In addition, there was a big difference in the flexibility of their necks.
However, the mechanism that allows giraffes to move their necks flexibly has not been elucidated.

A few years ago, a paper revealed that there is an eighth bone in the giraffe’s neck.
That bone is called the “first thoracic vertebra,” which is the bone that serves as the axis of the back.
It was found that this vertebra allows giraffes to have a wider range of motion in their necks.

The function of this thoracic vertebra makes it possible for giraffes to eat leaves from high trees and drink water from the ground.

Is it true that a giraffe has five horns?

Many people believe that giraffes have two horns.
However, giraffes actually have five horns.
One is located on the forehead and the other two are located behind the ears.

These horns are called “ossicones.”
Although it is easy to confirm the three horns, many giraffes have individual differences in the two horns behind their ears, making them difficult to find.

If you have the opportunity to see a giraffe at a zoo, try looking for them.
It is rare to find a giraffe with visible horns behind its ears.

Why are giraffe tongues black?

Giraffes’ tongues are not pink like humans’, but rather black.
It may seem strange that their tongues are black.

The reason why giraffes’ tongues are black is because melanin increases to protect their tongues from ultraviolet rays.
When giraffes eat for long periods of time, their tongues are exposed to strong ultraviolet rays in Africa.
Therefore, melanin darkens their tongues to protect them from absorbing ultraviolet rays.

How long does a giraffe sleep?

It is said that herbivores sleep 2-3 hours less than carnivores, who sleep for more than 10 hours.
We can see that there is a big difference in sleep time between predators and prey.

So how short is the sleep time of giraffes, which are herbivores? Actually, giraffes sleep for only about 20 minutes.
They can only sleep deeply for 1-2 minutes of those 20 minutes.
Giraffes are not only the tallest animals but also the creatures with the shortest sleep time.

Why is the sleep time so short?
We will explain the reasons in three parts.

1）Because there is a risk of being targeted by carnivorous animals.
Giraffes, which are herbivores, do not know when they will be targeted by enemies.
They sleep with such tension, so they keep their sleep time very short and do not sleep deeply.
In addition, they lower their metabolism to conserve energy and prepare to fight against enemies.

2）Because it is necessary to prioritize meals over sleep time.
Giraffes eat leaves, but they need to eat a lot to get the nutrients they need because leaves are very low in calories.
Therefore, they spend time on meals even if it means reducing their sleep time.
Because their bodies are large, they need to keep eating to meet their nutritional needs.

3）Giraffes have a body structure that allows them to live even with short sleep times.
In the case of humans, if there is only 20 minutes of sleep time, it can affect their personal life.
Sleep plays various roles such as repairing the body and brain while sleeping.

Sleep plays an important role for living things, but can giraffes repair their bodies and brains with short sleep times?
Actually, giraffes reduce their metabolism to reduce damage to the brain and reduce the number of places that need repair.
Giraffe bodies are designed so that they are not affected by short sleep times.

Why do giraffes mate with males?

It is said that 90% of giraffe mating is done between males.
Why does such a situation occur?

Giraffe males fight each other with “necking” to mate with females.
During the fight, the males are in an excited state.
If the fight continues for a long time, they mistake their excitement for sexual excitement.

It’s like the suspension bridge effect.

What role does the giraffe pattern play?

Giraffe patterns serve two purposes.

1）Regulates body temperature and cools the body.
Under the brown skin that serves a role in temperature regulation and cooling the body, there are many capillaries.
By circulating blood in the brown part and releasing heat, the body can be cooled.
It is also called a thermal window.

2）The pattern serves as camouflage and hides the giraffe from enemies.
The giraffe’s pattern can blend into the natural environment of Africa so that it is not targeted by enemies.
The natural environment of Africa has little greenery and is dominated by an image of soil.
The giraffe’s pattern is brown, so it has a color that can blend into the soil.

Both roles are evidence that the body has adapted to the natural environment of Africa.

Does the pattern of giraffes change depending on the type?

There are 9 species of giraffes.
Do different species of giraffes have different patterns?

1）Reticulated Giraffe.
As the name suggests, it has a mesh-like pattern and a clear contrast between brown and white.

2）Masai Giraffe.
It has a jagged pattern that looks like thorns on the brown part, and the area above the hoof is white.

3）Rhodesian Giraffe. (Thornicroft Giraffe).
The pattern around the neck is dark brown, and there is no pattern below the knee.

4）Nigerian Giraffe.
The characteristic is that there are many small spots.

5）Kordofan giraffe.
The pattern is similar to that of Masai Giraffe, but there is no pattern on the belly or inside of the legs, and it is white.

6）Nubian giraffe.
It has a light yellow color and a large square pattern.

7）Ugandan giraffe (Rothschild’s giraffe).
It doesn’t have a clear color pattern like Reticulated Giraffe, but it has white below the knee.

8）Angolan Giraffe.
The characteristic is a V-shaped cut pattern.

9）South African Giraffe.
It has a chestnut color and an irregular shape of square or octagonal patterns that continue to below the knee.

Why are giraffes included in the list of endangered species?

Not all giraffes, but four of the nine species are said to be endangered or on the verge of extinction.
The number of giraffes was 150,000 in the 1980s, but it has decreased to 90,000 in 2015.
In just 35 years, nearly 60,000 giraffes have disappeared.

The reason for the decrease in the number of giraffes is that they are being poached by humans and their habitat is being lost.

Giraffe bones and tails are sold as decorations, so they are illegally hunted and captured.

In addition, as the population increases, land is being developed and the habitat of giraffes is decreasing.
As a result, giraffes are being captured because they damage crops or are hit by cars.

We must not forget that while giraffes are kept in zoos as a matter of course, wild giraffes are decreasing in number every year due to human behavior.

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Type of giraffe.

【Reticulated Giraffe.】
・Reticulated Giraffe.

【Masai Giraffe.】
・Masai Giraffe.
・Rhodesian Giraffe. (Thornicroft Giraffe).

【Giraffa camelopardalis.】
・Nigerian Giraffe.
・Kordofan giraffe.
・Nubian giraffe.
・Ugandan giraffe. (Rothschild’s giraffe).

【Giraffa giraffa.】
・Angolan Giraffe.
・South African Giraffe.

Bibliography.

ウィキペディア
https://ja.wikipedia.org/wiki/キリン

CNN　「世界一長身のキリン、身長5.7メートル　ギネスが認定」
https://www.cnn.co.jp/fringe/35157602.html

THE ANIMALS「キリン」
http://animals.main.jp/mammals/giraffe001.html

論文　キリンの首は、もっと長い－解剖学的解析による、8番目の「首の骨」の発見－
https://www.a.u-tokyo.ac.jp/topics/2016/20160203-1.html　(2016.2.3)

雑学ネタ帳　「キリンの角は何本あるか」
https://zatsuneta.com/archives/006585.html

FUNDO　「キリンは超ショートスリーパー⁉驚きの睡眠時間で過ごしていた!」
https://fundo.jp/303676

exciteニュース「キリンの交尾、9割はオス同士⁉獣医が明かした動物たちの同性愛事情」
https://www.excite.co.jp/news/article/Tocana_201610_post_11160/?es=true

絶滅危惧種リスト「キリンの網目状の模様には大きな意味が!驚きの事実!」
https://endangered-species.biz/archives/128

博識人ブログ「キリンは全何種類?詳しく解説!」
https://hakushikijinblog.com/giraffe-type

ecotopia 「キリンの亜種が絶滅危惧指定!その原因は?」
https://ecotopia.earth/article-2658/

アイキャッチ画像
https://pixabay.com/images/id-1330814/