期刊:Cornell University Press eBooks [Cornell University Press] 日期:2016-08-12卷期号:: 104-120
标识
DOI:10.7591/cornell/9781501704673.003.0007
摘要
Abstract This chapter examines how trunks, and for that matter elephants, came to be by referring to Rudyard Kipling's “The Elephant's Child.” It first looks at fossils unearthed in the Fayum district of Egypt and the discovery of bones from a pig-sized animal called Moeritherium. It then discusses the descent of elephant testes to explain elephant origins as well as the presence of funnel-shaped kidney ducts called nephrostomes in all elephant fetuses. It also considers the elephant's minuscule embryonic trunk as a means for deep snorkeling; the evolution of proboscids and the trunk by natural selection; the flexible hyoid structure as a distinctive feature of elephants; and the role of tusks in sexual selection in elephants.