<<返回上一页

Elephants are just big water babies

发布时间:2019-03-08 06:19:08来源:未知点击:

THE first study of early elephant embryology supports the idea that elephants evolved from an aquatic mammal with a trunk that functioned as a snorkel, say biologists in Australia. Ann Gaeth of the University of Melbourne in Victoria and her colleagues examined fetuses from African elephants and found funnel-shaped ducts in their developing kidneys. Such ducts are unknown in the kidneys of other viviparous mammals, but they are characteristic of freshwater fish and frogs ( Proceedings of the National Academy of Sciences, vol 96, p 5555). Together with other fetal features such as testes kept within the abdomen—a streamlining adaptation found in other marine mammals—the results indicate that the ancestor of elephants “probably spent millions of years in the water”,