The ancestors of the modern giraffe began developing their super long necks as far back as 16 million years ago, beginning the long process of the giraffe slowly but steadily evolving into the tallest living terrestrial animal, new research has discovered.
In a study published last week in the journal Royal Society Open Science, researchers from the New York Institute of Technology reported how the examined vertebrae from the backs of more than 70 different animals belonging to 11 different species, and discovered that even before the modern-day giraffe emerged, the basis for its elongated neck was already being formed.
According to the Smithsonian and National Geographic, lead investigator Melinda Danowitz and her colleagues studied the second and third vertebrae in the neck. They discovered that the protogiraffe candidate Prodremotherium and an early giraffe known as Canthumeryx each had developed neck bones that were longer in proportion to their width 16 million years ago.
In fact, the long neck bones appear to pre-date the emergence of giraffidae, the subgrouping for these creatures, from other types of two-toed animals, the study authors wrote. Also around this time, the giraffe lineage split, with the vertebrae of one group shrinking and the vertebrae of the other group lengthening, explaining the different body structures of the giraffe and okapi.
Giraffe neck evolution involved many stops and starts
It wasn’t until approximately 7.5 million years ago that the first truly long-necked, modern-type giraffe emerged, and the process was not a quick one, according to National Geographic. The neck bones of the giraffe ancestors typically grew longer from either the top or the bottom one generation at a time—before the neck of the modern giraffe ultimately elongated in both directions.
“We propose that cervical elongation precedes Giraffidae,” the study authors wrote. “We also believe that cranial lengthening is the first stage of elongation seen in the family, followed by caudal lengthening, which accounts for the extreme Giraffa neck elongation. Mathematical transformation further supports the proposed stages, where both cranial and caudal elongation contribute to the illustrious [modern-day giraffe] G. camelopardalis neck.”
But, the overall development of the giraffe neck was not a smooth and consistent process, with many “starts and stops” as a “small-statured herbivore” developed over time into “a towering, checkered browser.” At least one (and possibly more) giraffe lineages went back to smaller necks, they noted, and long necks was never truly an evolutionary goal.
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Feature Image: Thinkstock
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