Some may travel a portion of the way, some may not at all. Gray whales are benthic feeders. That means they eat food they find at the bottom of the ocean. Gray whales are baleen whales. Baleen whales, also known as mysticetes , do not have teeth.
Baleen whales have plates of baleen that hang from the upper jaw.
The baleen is used to filter food from the water. In the past, whales were hunted for baleen. Before we had plastic, the baleen was used to make corset stays, combs, even buggy whips. Some cultures still hunt whales for food. This subsistence hunting is regulated and does not affect the population as a whole.