括约肌

hǎi tún méi yǒu shēng dài dàn què néng fā shēng yī gè yóu kǒu shào shēng zhī zhī shēng shēn yín shēng chàn yīn hé kā chā shēng zǔ chéng de fù zá xì tǒng shì yóu pēn shuǐ kǒng nèi de kuò yuē jī chǎn shēng de

海豚没有声带，但却能发声：一个由口哨声、吱吱声、呻吟声、颤音和咔嚓声组成的复杂系统是由喷水孔内的括约肌产生的。

Dolphins lack vocal cords, nevertheless creating sounds: a complicated system of whistles, squeaks, moans, trills, and clicks are produced by sphincter muscles inside the blowhole.