They are warm-blooded. But instead of lots of hair (like most
mammals), they have blubber to keep them warm! you notice the
few bristly hairs in the top picture? Young gray whales have
only a few hairs around their mouths, but they soon lose them.
Adults may have some bristles on their chins. the bottom
picture, you can see dimples where hairs would would slow whales
down in the water. They evolved over millions of years to have
streamlined bodies protective layers of blubber