Giraffe Neck Elongation Revealed In Fossil Evidence, New Study Shows

Have you ever wondered why giraffes have such long necks? Scientists have long thought it was to simply help them find more vegetation on higher trees or to develop a specialized method of fighting. However, a recent study revealed that the giraffe's long neck evolved in several stages, as one of the animal's neck vertebrae stretched first toward the head and then toward the tail a few million years later.

"It's interesting to note that that the lengthening was not consistent," Nikos Solounias, a giraffe anatomy expert and paleontologist at New York Institute of Technology's College of Osteopathic Medicine, said in a news release. "First, only the front portion of the C3 vertebra lengthened in one group of species. The second stage was the elongation of the back portion of the C3 neck vertebra. The modern giraffe is the only species that underwent both stages, which is why it has a remarkably long neck."

For their study, researchers examined 71 fossils of nine extinct and two living giraffes.

"We also found that the most primitive giraffe already started off with a slightly elongated neck," Melinda Danowitz, a medical student in NYIT's Academic Medicine Scholars program, added in the release. "The lengthening started before the giraffe family was even created 16 million years ago."

Researchers were truly able to see the phases of giraffe evolution when they analyzed anatomical features of the fossils and compared them to other family members. They found that the cranial end of the vertebra initially stretched seven million years ago in the species known as Samotherium, an extinct relative of today's modern giraffe. The second stage occurred one million years ago, when the back or caudal portion elongated, according to the release. 

Today, modern giraffes' C3 vertebra, which helps support its head, is nine times longer than its width. To put this into persective, this means their C3 vertebra is roughly the length of an adult human's humerus bone, which stretches from the shoulder to the elbow.

While the necks of modern day giraffes were getting longer, the okapi ended up on a different evolutionary track with a shorter neck, according to the researchers. An okapi is a close relative of the modern-day giraffe and has stripes similar to zebras. They are mainly found in central Africa and are the only other living member of the giraffe family. 

Next, researchers plan to study the evolution of giraffe's long leg bones.

Their study was recently published in the journal Royal Society Open Science. 

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