Giraffes have so many intriguing features. They have weirdly long bluish-purple tongues and feet as large as a 12-inch diameter plate. Then there’s the distinct coat pattern which is unique to each individual — similar to human fingerprints and snowflakes. However, one of the most impressive features of the giraffe is its height. Standing at a height of 14 to 18 feet, giraffes are the tallest living animals in the world. They are so tall that even a newly born baby giraffe is taller than an average human. Part of what makes giraffes so tall is their long necks.
The giraffe’s neck alone takes up about 38 percent of the animal’s total height. They undoubtedly have the longest neck of any animal species, and this unique feature allows them to do some cool stuff. But why do giraffes even have long necks? What does the neck really do? Read on to find out.
Why Did Giraffes Evolve Long Necks?
Why and how the giraffes came to have such long necks is still somewhat of a mystery for scientists. Although scientists have put forward different ideas over time, two of these ideas are more popular based on their plausibility. These two theories include the following:
1. To Reach Food Growing On Taller Plants
One of the most accepted theories is that of natural selection, which proposes that the giraffes developed such long necks as an adaptation to help them survive food competition against other animals in their habitat.
The famous scientist Charles Darwin explained this idea in the 6th edition of his famous book “The Origin of Species.” He proposed that in an environment with a limited food supply, giraffes with longer necks would have survived better than others with shorter necks. Giraffes are believed to have gotten their long necks some 12 to 14 million years ago. That period was very harsh, dominated by dry arid savannahs.
As vegetation decreased, competition for food increased, giving the long-necked animals that could reach foliage higher up on the trees an upper hand over others. The longer-necked individuals became more successful reproductively, while the shorter varieties eventually died off. This allowed individuals with even longer necks to develop over time.
Objections to This Theory
Interestingly, even though this theory is fully-credited to Darwin, he did not present it as an explanation for the giraffe’s neck in the first edition of his book. Instead, the first book focused on other aspects of the giraffe’s evolution, like its tail (with no reference to the animal’s long neck at all).
The possible scenario of how the giraffe’s neck came to be was originally developed as an objection to Darwin’s theory by George Jackson Mivart.
Mivart had noted possible loopholes in Darwin’s natural selection theory, claiming the giraffe’s long neck was evidence of the theory’s limitations. He argued that if natural selection was the reason for growing such long necks, other animals would have developed the same structure too. Similarly, it would make no sense for the giraffe to grow into such a massive size if the food was indeed scarce, as this would be counter-productive (bigger animals need more food to survive).
In response, Darwin wrote about the giraffe’s long neck in the 1872 edition of his book. He accepted Mivert’s premise of giraffes developing long necks due to competition for food and explained why other herbivores did not adopt the same adaptation. Different animals tend to adapt differently to the same situation. Hence, individuals typically develop varying adaptations that would eventually distinguish them instead of evolving the same way. As for the drought situation, Darwin pointed to the presence of giraffes in present-day locations with drought-like conditions as evidence that evolving into bigger sizes would not have been a disadvantage for the giraffes.
2. Reproductive Adaptation
More recently, scientists have come up with a second possible explanation for the giraffe’s long neck. Some scientists in the mid-90s discovered a bizarre prehistoric giraffid with a long neck and a reinforced skull which shows that members of the species headbutted each other. This is a behavior seen in many animals with antlers or horns today.
Discokeryx xiezhi, which lived about 16 million years ago, provides some clues into the possible habits of this group of animals. Some scientists believe that the penchant for in-fighting among prehistoric giraffes allowed their necks to grow longer.
Objections to This Theory
The idea that giraffes developed longer necks for fighting is very controversial and raises many questions. For instance, if a giraffe’s long neck was primarily for fighting, why is it prominent in females too? Also, not only do the females have long necks, they continue to grow throughout the animal’s life and grow much faster than males.
A Little Bit of Both
Despite the different controversies, we can all agree on one thing. The idea that the neck has successively increased in length is way more complex than it sounds. There are many factors to consider before a befitting conclusion can be made on why the animal’s neck is so long. In fact, considering the fact that giraffes use their neck for a lot of things, the development of longer necks might have been a response to a combination of factors instead of just a single one.
How Giraffes’ Necks Are Built
The giraffe has seven long vertebrae on its neck. It has a ball socket joint between its axis and atlas vertebrae. With this, a giraffe can turn its neck to rub its nose against its back. The neck also comprises a network of strong muscular ligaments for support. An example of this is the large nuchal ligament that runs from the tail all the way up to the skull. In summary, a giraffe’s neck is a perfect balance of weight, strength, and flexibility.
Interestingly, despite being so long, the giraffe’s neck cannot reach vegetation on the ground. A thirsty giraffe would have had to spread its forelegs or bend its knees to drink water.
What Do Giraffes Use Their Necks For?
Since giraffes have such long necks, what do they need them for? The following are some of the things a giraffe’s neck can be used for.
Giraffes are massive browsers that feed on the broad leaves and the buds of trees and shrubs. Their long necks put them at an advantage against other herbivores in the same location. Giraffes can easily snatch up leaves from the top of the Acacia tree or any other large plant for food. They also have long tongues and the atlantoaxial joint that allows vertical movement. These features allow the giraffe to comfortably access the top of small trees and a variety of foliage out of the reach of other animals.
The act of necking is prevalent among male giraffes competing for a mate. Necking is a fancy name for the fight for dominance among the species. In an ongoing fight, the males swing their long necks around and hit each other with their heads. The male with a longer and thicker neck is more likely to end the fight victorious. There is also a tendency that they will most likely mate and give birth to offspring with longer and stronger necks. The individual that loses, on the other hand, may lose consciousness, suffer serious injury, or even die. He may even probably be forced to live with the shame of his defeat.
The tallest mammal on earth will definitely have one of the best views of its environment. Thanks to its long neck, a giraffe can spot its predators from a great distance. They have a wide-spanned peripheral vision that can see across their territory and even behind them as well.
While it might seem like a straightforward question, it’s difficult to tell for sure why and how giraffes managed to get such long necks. It’s safer to say that the theories put forward so far are fairly accurate, and a combination of these factors may have contributed to the long necks of this species.
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The photo featured at the top of this post is © Wim Hoek/Shutterstock.com
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