通过双鼻孔呼气，收缩中、下腹部。
Exhale through both nostrils , contracting the middle and lower abdomen portions .
比起尖鼻子的鲨鱼来说，双髻鲨的鼻孔相距比较宽。
BOB DOUGHTY : Hammerhead sharks have nostrils that are more widely spaced than those of sharks with pointed noses .
双鼻孔