Translation guide
The English word 'dolphin' refers to the marine mammal. In Japanese, the most common and general term is イルカ. There is also a less common term 海豚, and a specific term for the dolphin fish (mahi-mahi) シイラ, which is not a mammal but is sometimes confused.
Referring to the aquatic mammal of the family Delphinidae.
Referring to the fish Coryphaena hippurus, commonly called 'dolphin fish' or 'mahi-mahi' in English. Not a marine mammal.
The Japanese word for the dolphin fish (mahi-mahi). Important to distinguish from the mammal イルカ.
In English, 'dolphin' can refer to both the marine mammal and a type of fish (mahi-mahi). In Japanese, these are completely different words: イルカ for the mammal and シイラ for the fish. Using イルカ to refer to the fish will cause confusion.
Yesterday, I saw a dolphin show at the aquarium.
イルカはとても知能が高い動物です。
Dolphins are very intelligent animals.
The kanji representation of イルカ. Rarely used in modern writing; almost always written in katakana. May appear in literary or formal contexts.
海豚は古くから日本の海で見られてきました。
Dolphins have been seen in Japanese waters since ancient times.
シイラはハワイではマヒマヒと呼ばれています。
The dolphin fish is called mahi-mahi in Hawaii.