Sea Mammals are exactly that – mammals
(animals that bear live young and then nurse
them) that live in the sea
. They once lived on land. They had evolved
from the sea, from that first algae
, into the fish that crawled out of the water. They learned to breath air and walk
. Then they returned to the sea.
The skeletons I’ve seen of sea mammals show finger bones in the fins. It’s almost eerie.
Sea mammals include dolphins, whales, manatees, etc. These animals have lungs rather than gills and must return to the surface for air.
Whale sharks are not sea mammals – they are fish. They have gills.
Why did so many animals return to the sea?