The Difference Between Dolphins and Whales
Both dolphins and whales are classified as infraorder Cetacea, Odontocetes, and there are no biological differences.
イルカとクジラの違い
The difference between dolphins and whales is just their length of bodies.
イルカとクジラはどちらもクジラ目ハクジラ亜目に分類され、生物学的に差はあありません。
Dolphins are small ones of Odontocetes, and whales are large ones of Odontocetes and all of other Cetacea.
どのように呼び分けているかというと、体の大きさです。
The border of them is often defined as three to five meters.
イルカはハクジラ類のうち小型もので、クジラはハクジラ類のうち大型のものと、ヒゲクジラ類全てです。
By the way, the largest specie is: blue whale in Cetacea (also in all animals), sperm whale in Odontocetes, killer whale in dolphins.
イルカとクジラの境界は、3〜5 m とされることが多いです。
