noun
basking shark
A large, slow-moving shark (Cetorhinus maximus) that feeds on plankton. The name is thought to come from the shark's wrinkled skin resembling an old woman (姥).
ウバザメはプランクトンを食べる大きなサメです。
The basking shark is a large shark that eats plankton.
ダイバーがウバザメの群れに遭遇した。
The divers encountered a school of basking sharks.
ジンベエザメ (whale shark) is also a large filter-feeding shark, but it has a distinct spotted pattern and is more commonly known. ウバザメ is less frequently encountered and has a more uniform coloration.
The name ウバザメ is thought to derive from 姥 (uba, 'old woman') + 鮫 (same, 'shark'), referring to the shark's wrinkled skin. The exact historical origin is uncertain.