noun
milk shark
A small species of requiem shark (Rhizoprionodon acutus). The name is usually written in katakana.
ヒラガシラは沿岸の浅い海に生息する小型のサメです。
The milk shark is a small shark that inhabits shallow coastal waters.
The name ヒラガシラ literally means 'flat head', referring to the shark's head shape. The exact derivation is uncertain.