Why does a giraffe have such a long neck

Learn more. The neck of a giraffe Giraffa camelopardalis is a marvellous thing. How could such a structure have evolved? This question is not just a throw-away. For the past century and a half, naturalists have been vexed by the long neck of the giraffe. There is an ongoing anatomical debate about whether giraffes have only seven neck vertebrae or eight, the extra one being a modified part of the back.

If you want to read up on the technical details of this hypothesis, see Nikos Solounias' paper on giraffe anatomy. Darwin, I was taught in my high school and college lectures, proposed that among an ancestral population of giraffes there were individuals which just happened to have slightly longer necks than their fellows.

This allowed them to reach higher branches, and as a consequence, these giraffes were more reproductively successful since they persisted on an untouched food source while giraffes of lesser stature perished due to competition.

Darwin did not explicitly consider the neck of the giraffe until much later, and when he did, it was in response to one of his most serious critics. In , the naturalist George Jackson Mivart published a book-length rebuttal to evolution by natural selection titled On the Genesis of Species. Like many other late 19th century naturalists, Mivart accepted evolution but rejected natural selection, and one of the major points of his book was that natural selection could not account for the intermediate stages between an ancestral and descendant form.

Likewise, the changes which must have occurred between the ancestral and modern giraffe must have extended beyond neck length alone. Various bits of anatomy and physiology would have had to have carried favourable variations in order for it to even be possible for giraffes to evolve long necks, and these changes — which would have increased the mass of the giraffe — would have required that it take in even more food under stressed, drought conditions.

Mivart had set up a straw man argument, but Darwin took this criticism seriously. Given the competition which would have occurred among herbivores during times of drought, Darwin surmised, it is not surprising that giraffes can reach a level of vegetation that others cannot — competition would drive forms apart rather than keep multiple forms in close competition by adapting them in the same way.

Wallace considered this same point over a decade earlier. Giraffes, like any other species, expressed variation, and the ability of individuals to reach food inaccessible to others would have led to the success of the taller forms. And, as far as drought conditions were concerned, Darwin countered that living giraffes were abundant in Africa. If the large, modern animals could survive temporarily stressed conditions, then why not intermediate forms which have since been replaced?

What Darwin did not do was present a detailed, historical explanation for the form of the giraffe. Indeed, Darwin was typically careful in handling the history of life, and even when he was privately enthusiastic about fossil forms which exhibited transitional features — such as the feathered dinosaur Archaeopteryx — in his public works he avoided laying out precise step-by-step scenarios which would have taken place in the distant past.

Darwin knew that palaeontologists had only just begun to probe the fossil record, and so outlining phylogenies or tracing evolutionary lines of descent was a risky manoeuvre since those findings would almost certainly have to be revised. Giraffe can browse the crowns of small trees; big bulls can reach higher than cows.

Giraffe feed mainly on broad leaved deciduous foliage in the rains and on evergreen species in other seasons. A reinforced skull usually absorbs the impact of these blows, but occasionally an animal is knocked unconscious and very rarely even dies during such a fight. 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. Surprisingly, even with its long neck, the giraffe has the same number of vertebrae in its neck as humans and other mammals. Giraffe have seven cervical vertebrae, but each one can be about 25 cm long.

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We see this on cards all of the time : And what is with their pattern? It is similar to a leopard's and makes us think they are mimicking. We are really wondering this morning! Wonderopolis Sep 19, Stringer's 4th Grade Home We are still wondering about why giraffes fight other giraffes and how big a giraffe baby could be. We were also thinking about the similarities between a giraffe and some long necked dinosaurs Casimiro Apr 17, Well, they have long necks because they reach their food in the trees.

The giraffe only lives to be about 25 years old. The horns on the giraffe's head are not for defense. It uses it to push the branches out of the way so they can get more food. Wonderopolis Apr 17, Pruetz's 4th Grade Orange Apr 20, Wonderopolis, Thank you very much for providing this wonderful video about giraffes. We had a lot of fun and enjoyed our time learning.

Pruetz's 4th Grade Orange Group. Wonderopolis Apr 20, Team McNeil 9 Apr 17, Hi Wonderopolis! I was very interested when I found this topic! I love giraffes! One new fact that I learned was that giraffes fight by beating each other with their heads and necks, and that this process is called "necking". I also didn't know that giraffes have a deadly kick, and that they can run up to 30 miles per hour!!

I also learned two knew vocabulary words! One is drought, which means that there is hardly any water or rain in an area. Another vocabulary word that I learned was scarce, which means that a natural resource, animal species, etc Campbell's 5th Grade Yell Apr 17, Wonderopolis, We are students at Condit Elementary and we are in the fifth grade yellow group.

We enjoyed reading and listening to the information about giraffes. We generated a list of questions and voted for one more thing to find out about giraffes. We would like to know if there is an animal that the giraffe is thought to have evolved from? Campbell's Fifth Grade Yellow Group. Campbell's 4th Grade Yell Wonderopolis, Our fourth grade yellow group also enjoyed your information on giraffes.

They had some questions about giraffes around the world too. We would like to know how tall and heavy the largest giraffe in all of history has been? Campbell's fourth grade yellow group. Campbell Apr 12, Wonderopolis, We enjoyed your post about giraffes. We all had some questions that were not answered in your video and we voted on one to ask you. We are curious to know more information about a giraffe's heart.

Is it bigger than a human heart? We know that the heart gives out after about 25 years, but we wonder if it proportionately bigger than our heart?

Wonderopolis Apr 12, Megan Apr 10, Thanks for a great wonder. Giraffes are my favorite animal, but I think more could of been in the article! Wonderopolis Apr 10, Team Unger 8 Mar 29, In this article, I learned some new facts about giraffes.

One of them is that they can run 30 miles per hour! Another thing I learned is that their necks reach more than 7 feet tall! Also I learned what necking is-when they fight.

Finally, I learned the word foliage. I do have one question; how long are the young giraffes necks when they are born?

Thanks for making me wonder! Wonderopolis Mar 29, Bob Mar 23, Wonderopolis Mar 24, Kamryn Mar 15, Wonderopolis Mar 15, They're pretty awesome, Kamryn, we agree! Landon Mar 12, Giraffes have long necks because they use them to eat leaves. I also noticed that they have long legs, long tongues and long tails. Wonderopolis Mar 12, Carry Mar 10, If I had a long neck, I don't know what I would do with it, but somehow giraffes use them! I really enjoyed this wonder today!

Bye for now, I'm going to comment on the wonder of the day! Wonderopolis Mar 10, Alex Mar 8, I think giraffes have long necks so they can get leaves from trees. Wonderopolis Mar 8, Wonderopolis Mar 7, Way to go! Flinn's Kindergarten Class Mar 5, We are still wondering how tall a teenager giraffe is? How long are girl giraffes? We learned giraffes are 15 feet tall. Giraffes kick and bend necks when they see predators. Giraffes have long necks to see predators. Giraffes are the tallest land animals in the world.

Wonderopolis Mar 5, Good Wonder!! This made my brother think why giraffes have long necks! Thanks very much! Wonderopolis Mar 3, Paige Mar 2, Dear Wonderopolis, Cool wonder! I have no idea why giraffes have long necks! I think tomorrow's wonder is about bugs. Wonderopolis Mar 2, I didn't really know all that about Giraffes!

What I really appreciated is that they can see a predator a mile away and that they can run as fast as a race horse!!! I love giraffes!!!!!!!! I love their pattern it is beautiful!!!!!! What is your favorite animal print?? It's my friend, Hannah Gibbs' birthday!!! You should say happy b-day. Emmz Mar 1, Hello Wonderopolis!

I would like to ask a favor. I suffer from milk allergies. Could you do a wonder to educate others about it? I was also wondering could you make a small donation to FAAN a reasearch team for finding a cure. It would really mean a lot to me and others. Thanks, Emmz. Wonderopolis Mar 1, Food Allergy Girl Mar 1, I loved this wonder.

I wanted to ask you a quick question. Can you do a wonder about milk allergies? I suffer every day with them. You changed my life with the peanut allergy wonder. I am keeping the faith. Dear wonderoplis. Thanks for saying I rock. You and your website rock, too. Ella :. Gallagher Gang Mar 1, We have just been introduced to this exciting website.

Thanks for sharing all these wonders with us. We are learning a lot. Here are our predictions about tomorrow's wonder: Cat: A cat got your tongue! Anteater: We liked someone els'se idea that they might get their tongue stuck in a knot. AP Mar 1, Giraffes are cool. They have really long necks. Now I really want to go to the zoo and see the giraffes. Daniel Mar 1, How big can a Giraffe get. What is the tallest Giraffe on record. Blevins' Class Mar 1, Our class was surprised that giraffes aren't as smart as other animals.

It's crazy that when giraffes are born they are as tall as an average adult. We also didn't know that they have the highest blood pressure of all animals and the deadliest kick. The video was funny. Those tongues were so long! Jonathan Mar 1, I wish I was a giraffe so that I could have a long neck! Dear wonderopolis. I was wondering the same thing, but I know Kennedy'a Class Mar 1, Dear Wonderopolis, Our class from Room liked the giraffe video. Can you please find a video to explain why giraffes have such long tongues?

The giraffes were so cute! Are they really as "dumb as a sack of hammers"? The video was funny--our entire class loved it. Have a great day! Kids in Room PS-Ella logs onto Wonderopolis each morning before school and she posts her own comment! She loves this site!