Unfortunately, evolutionists incorrectly teach that the whale is not a fish but rather a "mammal" like a dog, or a cat, or a gorilla, or an elephant, or a zebra, or a bear, or a goat, or a fox, or a bat--this is not true. Anyone unaffected by the proclamations of evolutionists would look at a picture of a blue whale swimming and see a great, huge, colossal, humongous fish swimming through the sea, not a "mammal" akin to a dog or a cat. We know that the whale is a fish because the word of God, the Authorized Version of the Bible, makes this very clear--in Jonah chapter one we see that the prophet Jonah was swallowed by a great fish and then in Matthew 12:40, the Lord Jesus Christ reveals that that great fish was a whale. Let's look at the scriptures--
The prophet Jonah was swallowed by a great fish--
Now the LORD had prepared a great fish to swallow up Jonah. And Jonah was in the belly of the fish three days and three nights. Jonah 1:17
In Matthew 12:40, the words of the Lord Jesus Christ, our Creator, revealed that the great fish that swallowed up Jonah was a whale--
For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth.
The whale is exactly what it looks like--a fish, a huge fish that goes to the surface of the water for his oxygen. He was created with his own unique and amazing anatomy, physiology and habits according to what God ordained for him to have.
Unlike many fish, the whale gives live birth to its young ones, which many today call "calves" [Note: it is kine/cows have calves; fish do not have calves].