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