Some whales have fins, but not all species do. Some types of whales have dorsal fins similar to a dolphin's that help them to swim. More »

While a whale's fins are similar in structure and function to those of a fish, whales and fish are not closely related, so their similarities are defined as analogous, not homologous. The development of fins in two such ... More »

Whales have hair, as all species of whales are aquatic mammals. Instead of having scales, like most other marine animals, whales have a fine layer of hair over their bodies. More »

Killer whales, some species of sharks, Arctic wolves, polar bears, cougars, brown hyenas, various canid species and even other types of seals prey on seals. Some species of seals don't have any natural predators due to w... More »

Depending upon the species, whales can hear each other up to 1,000 miles away. Whales use their sounds to communicate and to navigate the ocean with echolocation. More »

Homologous structures, such as the fins of whales and the hands of monkeys, demonstrate that while a species may use structures for different purposes, the species shared a common ancestor. By definition, homologous stru... More »

Sharks and dolphins are alike in many ways, sharing several physical characteristics such as their side fins, dorsal fins and torpedo-shaped bodies. Although these animals vary wildly – one is cold-blooded and one is war... More »