Which whale species lacks a dorsal fin and has a mottled gray color?

The whale species that lacks a dorsal fin and has a mottled gray color is the gray whale.

Gray whales are easy to distinguish from many other baleen whales because they do not have a conventional dorsal fin. Instead, they possess a low dorsal ridge followed by six to twelve raised bumps, often called knuckles, along the rear part of the back. Their dark slate-gray skin is marked with irregular pale patches and scars.

Much of the mottling comes from parasites and the scars left after those parasites detach. Researchers use these stable patterns, along with photographs of the tail and back, to identify individual gray whales. Gray whales also have unusually short, cream-colored baleen and a relatively narrow feeding specialization compared with many rorquals.

The species is famous for one of the longest mammal migrations, traveling between Arctic feeding grounds and warmer breeding areas. It feeds largely by rolling onto its side and suctioning small organisms from seafloor sediment. Gray whales are sometimes confused with right whales, but right whales have different head shapes and lack the gray whale’s characteristic dorsal ridge and mottled scar patterns.