Findings in a study published in the Royal Society Open Science, revealed the specifics on the evolution of the giraffe’s long neck. Researchers said that the evolution occurred 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,” said Nikos Solounias, a giraffe anatomy expert and paleontologist at NYIT College of Osteopathic Medicine. “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,” Eurekalert reported.
Scientists gathered 71 fossils of nine different extinct and two living species from the giraffe family, and then analyzed them. The bones were found in the late 1800s and early 1900s, and were handed by several museums around the world.
Nikos Solounias and Melinda Danowitz, who were in charge of the evaluation of the fossils, discovered that the most primitive giraffe already started off with a slightly elongated neck.
“The lengthening started before the giraffe family was even created 16 million years ago,” said Danowitz, who is a medical student in the school’s Academic Medicine Scholars program, as Eurekalert informed.
However, the most important discovery came after the researchers studied anatomical features of separate fossils and compared them to the evolutionary tree. That was the moment when they realized there was a process of several stages involved during the evolution process.
Both Solounias and Danowitz discovered that the cranial end of the vertebra stretched initially around seven million years ago in the species known as “Samotherium”, and extinct relative of today’s modern giraffe, being the first stage.
The second stage was characterized by an elongation on the back or caudal portion around one million years ago. According to researchers, the C3 vertebra of today’s giraffe is nine times longer than its cross measurement, nearly as long as an adult human’s humerus bone, which can stretch from the shoulder to the elbow.
Researchers stated that they will continue with further studies in order to analyze the evolution of the giraffe’s long leg bones.
In addition, giraffes are not the only animals to have evolved long necks. According to National Geographic, the sauropod dinosaurs and aquatic plesiosaurs, for instance, stretched out to ludicrous lengths both by including additional vertebrae to the column and elongating those specific bones.
Source: Royal Society Open Science