https://en.wikipedia.org/wiki/Pakicetus

Did you know that present theory places whales and dolphins as the descendants of land-dwelling, pseudocanine predators that once inhabited Pakistan?

“Odontocetes and mysticetes split into two separate parvorders around 34 million years ago.

Whales are descendants of land-dwelling mammals of the artiodactyl order (even-toed ungulates). They are related to the Indohyus, an extinct chevrotain-like ungulate, from which they split approximately 48 million years ago. Primitive cetaceans, or archaeocetes, first took to the sea approximately 49 million years ago and became fully aquatic 5–10 million years later. Archaeoceti is a parvorder comprising ancient whales. These ancient whales are the predecessors of modern whales, stretching back to their first ancestor that spent their lives near (rarely in) the water. Likewise, the archaeocetes can be anywhere from near fully terrestrial, to semi-aquatic to fully aquatic, but what defines an archaeocete is the presence of anatomical features exclusive to cetaceans alongside other primitive features not found in modern cetaceans, like visible legs or asymmetrical teeth.”