The size of giraffe necks has become one of nature’s greatest mysteries. Therefore, these mammals became the protagonists of studies in all kinds of scientific disciplines. Many theories have tried to explain this rare feature. At first, the French naturalist Jean-Baptiste de Lamarck (1744-1829) proposed the solution that seemed the most plausible. Their necks were so long that giraffes were able to reach food at the top of the trees, thus developing this evolutionary advantage over other animals.
But science has shown that the answer may not be so easy. The recent discovery of a fossil belonging to a primitive species points to another possibility, and that is; Giraffes have stretched their necks for a much more fundamental reason: to gain preference from females to continue their lineage.
This was concluded by researchers from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences after studying the characteristics of living things, in a paper published in ‘Science’. Discokeryx xiezhi, a strange primitive giraffe found in the Asian country. After examining their bones, the scientists concluded that the giraffe’s neck evolved this way to compete against other males during courtship.
And the thing is, for a male to be the most important in the tower hierarchy (as the herds are known) – and therefore the most coveted to breed with the females – he must prove to be stronger than the males. rest. In this sense, this study concludes that: Having a genetically taller stature allows them to do more damage to their opponents.
During fierce courtship fights, male giraffes fight each other by throwing their heavy heads (very sturdy and full of bumps) towards the weakest parts of their opponents to get them out of the breeding game.
The fossils in this study were found in strata of the early Miocene (about 17 million years old) in the Junggar Basin in northern China. A complete skull and four neck vertebrae of this protozour were found in the area they named. Discokeryx xiezhi.
“The individual had many characteristics that made him unique among mammals,” says Tao Deng, a professor at the Institute. What surprised them most about this animal was that it had a single protrusion instead of two (as current giraffes usually have). “It’s a large, disc-shaped ossicon in the middle of its head,” Deng says. Actually, this Unicorn This is what gives it this peculiar name, as the xiezhi is a unicorn creature in Chinese mythology.
this Discokeryx xiezhi It also has very robust cervical muscles and complex joints connecting the head and neck. According to the research, these features are closely related to head-on collisions at high speeds. actually andThis animal is probably the vertebrate best adapted to skull collisions.
“Both live giraffes and Discokeryx xiezhi Therefore, although the morphology of their skulls and necks is slightly different, “both are associated with male courtship fights, and both have evolved in an extreme direction,” explains Shiqi Wang. reassures the researcher.
Apart from examining their behavior diskokeryx xiezhi, The research team also compared the antlers of various groups of ruminant animals, including giraffes, cattle, sheep, deer and pronghorns. They found that in the eyes of the researchers, giraffes have a much more diverse mound than other animals. In other similar animals, courtship fights are “more intense and varied.”
After examining the enamel of his teeth, the scientists came to the following conclusion: Discokeryx xiezhi lived in open grasslands and may have migrated during a particular season. 17 million years ago, the grassland ecosystem was very arid and less comfortable than forest. From here Researchers believe this fierce mating struggle may be related to the climatic stress they experience.
Seven million years ago, when the ancestors of giraffes appeared, the environment was very similar. The East African Plateau suddenly changed from a wooded environment to an open grassland, thus The first giraffes also had to find a way to adapt to the changes, and that was to attack their rivals with their long necks in order to mate.
These extreme struggles, together with sexual selection, caused the giraffe’s neck to lengthen rapidly over two million years to finally become the giraffes we know today.
Reference work: https://dx.doi.org/10.1126/science.abl8316
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