The giraffe has a long neck to be able to eat high-lying leaves, assumed the father of evolutionary theory Charles Darwin.
Now, new findings suggest that it is rather sexual selection that is behind it.
Chinese researchers claim that giraffe males’ quarrels over females have led them to develop such long necks. The research is based on an unusual fossil from the Miocene era that was found in northern China in 1996. The skull that was found was unusually thick at the base and was intricately put together with an enlarged neck vertebra and then vertebrae. One year after the find, it was established that the fossil was of a giraffe animal, a family that includes several extinct giraffe-like species but also today’s okapir and giraffes.
The distant relative of today’s giraffes was equipped with a built-in helmet and had advanced joints in the head and neck.
“It’s a cool story about a fantastic sexual weapon,” Ted Stankowich, an evolutionary ecologist at California State University, told the journal Science, where the study was published.
Horn helmet
The paleontologists and Shi-Qi Wang and Tao Deng at the Chinese Academy of Sciences x-rayed the fossil to examine how the parts were shaped and placed in relation to each other. In addition to the unusually thick cervical vertebrae, a bony plate with a thick helmet-like part of the horn on the head was also found.
The researchers compared the findings with other giraffe animals and also other animal species, including wild sheep and musk oxen. They concluded that the head and neck were designed in a way that effectively protected in quarrels with other males and indicates intense fighting for females. The fossil was named discokeryx xiezhi.
Rapid development
If the species developed its special helmet to fight for females, sexual selection may also play a role in the development of other species’ heads and necks, according to researcher Shi-Qi Wang.
– The development of necks is very fast and flexible and depends on the males’ fighting style, she says.
The discovery provides a new understanding of the giraffe’s neck development and suggests that the species ‘ability to eat leaves at the top of the trees was rather random and not the cause of the giraffes’ long necks, according to the researchers.
– They unequivocally show that this little giraffe must have used his helmeted head for combat, says Rob Simmons at the University of Cape Town who did not participate in the research project himself.
– I wish Charles Darwin lived while this discussion was going on. He would have been amazed, he says.