Gray whales are baleen whales, which are generally larger than toothed whales. It is thought that whales mate for life.
Whales are mammals deriving their oxygen from the air.
They have mammalian four-chambered hearts, hair and mammary glands. They evolved from a four-legged land mammal and still have remnants of pelvic bones. During the late spring of 1985, a fisherman in Benicia CA found the whale carcass wedged under a pier. In addition, two right ribs had been previously broken and one had not healed properly. He entered San Francisco Bay and, in spite of the quiet water and abundant food, he died.