Some likely reasons for the greater proportion of tuskless Asian elephants compared the African elephants may be due to strong selection in the past by humans killing the tusked male elephants and a gene in Asian elephants which is not as recessive.

與非洲象相比，由于人類過去過分捕殺有長牙的公象。形成非逆向基因淘汰的現(xiàn)象，而造成亞洲雄象無牙的比例較大的原因。

tuskless：無長牙的

tusk 長牙,獠牙 | tuskless 無長牙的 | tuxtlite 透輝石-硬玉,鈉透硬玉