Whales evolved from dog-sized land mammals!

[Catherine]

I heard something about this, but I hadn't had time to read it yet. It does make sense. They are full air breathers and they are carnivores.
For a carnivore ancestor to return to the ocean looking for food is possible and it seems that is actually happened.
Evolution has lots of time. Changes and adaptions can take centuries.
I think humans are a good example. We occupy the whole planet, but there are some extreme variations in different parts of the world.
There is a big difference between equatorial Africa and the Arctic circle. People can't even eat the same. Their needs are different.
People who live at high altitudes have some physical adaptations.

A land animal who wanted to take advantage of all the food in the ocean, would want to adapt to aquatic life.
Seals are definitely like dogs in some ways. They are still partly land adapted.
Whales however have gone all the way back to the ocean.
I wonder if any humans could do that?