Whales have fins and flippers that give them stability while swimming. Some whales have short flippers and others have long ones. The dorsal fins of whales vary in shape and size. The dorsal fin of a male orca is longer than that of a female. Not all whales have dorsal fins.
Some whales have smooth backs while others have knobs and ridges down the middle of their backs.
The underside of a whale is usually lighter than it's back. This is called counter shading. The blue whale is the largest of the Baleen whales. In fact, the blue whale is the biggest animal to live on earth. The record length for a blue whale is 110 feet.