Like us , giraffes today have seven neck ( or cervical ) vertebra . But their C3 or third cervical vertebra – which is nine times longer than it is all-inclusive – is about as long as the humerus os associate our shoulder to our elbow joint . allot to a unexampled sketch publish inRoyal Society Open Science , the elongation of the giraffe neck occurred in at least two phase . The cervical craniate stretched towards the head first , then towards the stern meg of year afterwards .
Why giraffes have such a long neck – for contact higher plant , specialised fight , or sexual survival of the fittest , for example – is still debated . To examine how their necks got so long , a team guide by Melinda Danowitz , from the College of Osteopathic Medicine at the New York Institute of Technology ( NYIT ) , analyzed and compare 71 vertebrae from 11 species in the fellowship Giraffidae : nine nonextant and two living members . These fogey bones were domiciliate in museum around the domain , and some were discovered over a century ago .
" It ’s interesting to note that that the protraction was not consistent , " study coauthorNikos Solouniasalso of NYIT said in astatement . " First , only the front portion of the C3 vertebra lengthen in one group of species . The second microscope 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 farsighted neck . "
On the left , fogy C3 vertebra of Samotherium , an extinct giraffid that lived seven million years ago . This mintage underwent the first stage of extension , but not the second stage . On the right , the C3 vertebra of a modernistic giraffe , which undergo both stages of extension . Nikos Solounias
The cranial ( or top ) end of the C3 vertebra stretched ab initio around 7 million years ago in an extinct species calledSamotherium major , a congeneric of today ’s giraffe . This was comply by a second stage of extension at the caudal ( or tail ) finish just a million years ago . The C3 ofSamotheriumand a modern camelopard are pictured above .
To their surprise , the team discover that this extension precede Giraffidae . " We also find that the most primitive camelopard already started off with a slightly elongated neck,“Danowitz said . " The lengthening started before the giraffe family was even make 16 million years ago . " A possible giraffe ancestor calledProdremotherium elongatumwas showing house of lengthening 25 million age ago . That mean neck length , the most distinguishing and pop attribute ofGiraffa , the team writes , is apparently not a defining feature of the household . Furthermore , as the giraffe ’s cervix was pose foresighted , the neck of another fellow member of the giraffe family – the Okapia johnstoni of central Africa – was shortening .
An example of neck elongation and shortening within the giraffe family . Nikos Solounias and Melinda Danowitz
