The thresher shark is named for its long, scythe-like tail.

Thresher sharks are mackerel sharks, of an Order (Lamniformes) that I've not seen before.

(Monad Shoal, Malapascua Island, Cebu, Philippines)

fish; shark; mackerel shark; pelagic thresher shark; Chordata; Chondrichthyes; sC Elasmobranchii; Lamniformes; Alopiidae; Alopias pelagicus