Darwin would have said that in a population of ancestral giraffes, some had slightly longer necks than others; the long-necked giraffes were better able to feed on tree leaves and as a result produced more offspring. Sauropod dinosaurs trump them easily: the dinosaur Mamenchisaurus , for instance, had a neck over 9 metres long… In the savannahs of Africa, it is by necking that male giraffes combat to win females. Ever since Darwin, this explanation for the evolution of large size and elongated necks in giraffes has been widely accepted. Jean Baptiste Lamarck, a French biologist who had an alternate evolutionary theory of biology to that of Charles Darwin, explained that giraffes have long necks because as they reached for leaves in high branches of trees, their necks became longer and stronger. How Giraffe Got his long Neck Darwin was the first to propose that long necks evolved in giraffes because they enabled the animals to eat foliage beyond the reach of shorter browsers.

Clearly, both Darwin's and Lamarck's conceptions of giraffe evolution were highly speculative. giraffes can feed on leaves at the tops of acacia trees. B Earlier short-necked giraffes stretched their necks over a long period of time. He might have added that all the short necked ones died, but all other extant ungulates have shorter necks, so I will give him the benefit of the doubt and say just luck did it.

Just because giraffes have long necks and long legs and can reach food high in the trees does not mean that a need to reach high browse was a causative factor in the evolution of those characteristics. The competing hypothesis is that giraffe necks evolved as a result of sexual selection. The latest and rather surprising theory, which hasn’t been proposed before, is that the giraffe’s long necks are the result of sexual selection—to compete for females, male giraffes developed a long neck. Their offspring, in turn, would inherit necks that were slightly longer.

Their cervical (neck) vertebrae have actually just extended in length, instead of adding more bones into the anatomy. So perhaps Darwin was right after all: giraffes use their long necks in order to avoid competition. If you have a long neck, runs the argument, you can eat leaves on tall trees that your rivals can't reach. Darwin's explanation of Giraffes having long necks would involve the longest-necked giraffes surviving, and then their children exhibiting more survival-important characteristics. Most people assume that giraffes' long necks evolved to help them feed. There are only seven vertebrae in mammal necks, meaning that the giraffe has vertebrae that are nearly a foot long each! The prodigious necks may have little to do with food, and everything to do with sex. C Ancient giraffes developed short necks and pass this trait to their offspring. According to Darwin, why do modern giraffes have long necks? That seemingly sensible explanation has held up for over a century, but it is probably wrong, says Robert Simmons. A Giraffes have always had long necks like the modern ones.

Darwin would have said that it happened by random luck.