Chinese researchers offered a new explanation for the evolutionary mystery of giraffes' long necks: They were elongated by head-bashing combat in competition for mates.
The study published in the journal Science last Friday revealed that the tallest land animal on Earth used its two-to-three-meter-long swinging necks as a weapon in the male courtship competition.
颈椎异常粗壮
In 1996, a team from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) under the Chinese Academy of Sciences discovered a 17-million-year-old fossil in the vast Gobi wilderness in northwest China's Xinjiang Uygur autonomous region.
The fossil features disk-shaped headgear equipped with a helmet-like horny cap, and particularly complex head and neck joints.
They analyzed the beast's inner ear structures, finding them distinct from the ox and the deer, and instead consistent with the extant giraffe.
It is named 'Discokeryx xiezhi' since its single ossicone recalls the xiezhi, a one-horned creature from ancient Chinese mythology.
极端求偶竞争
Wang Shiqi with IVPP and his colleague revealed in the new study that the strange beast's horns could serve as a cushion in the collision and the joints between the skull and cervical vertebrae could effectively protect the neck from breaking in the violent collisions.
It is similar to the East African Plateau about 7 million years ago when a forest environment degenerated into open grassland, prompting the giraffe ancestors to adapt to the new environment and become taller.
It is the courtship struggle that led to the rapid neck elongation over a period of 2 million years, and by dint of that advantage, giraffes occupied a relatively marginal, but rewarding ecological niche — feeding on high foliage out of reach of zebras and various antelopes, according to the study.
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