Whales and dolphins: basics

In short: Whales and dolphins are mammals that live entirely in water but originally descended from land-dwelling ancestors. As marine mammals, they breathe air and must surface regularly to do so.

In more detail: Both belong to the order Cetacea, which is broadly divided into baleen whales and toothed whales.

In detail

• Evolution: About 50 million years ago, the ancestors of whales evolved from land-dwelling mammals into water dwellers.
• Baleen whales: Species such as the blue whale use baleen plates to filter small organisms like krill out of the water.
• Toothed whales: Dolphins and sperm whales belong to the toothed whales and actively hunt prey such as fish or squid.
• Echolocation: Toothed whales use clicking sounds and their echo to detect prey and obstacles in murky water.
• Social behaviour: Many dolphin species live in complex social groups with pronounced communication.
• Intelligence: Dolphins show tool use, mirror self-recognition, and complex problem-solving abilities.
• Threats: Net fishing, pollution, and climate change endanger many whale and dolphin populations worldwide (fische-und-meerestiere, evolution-grundlagen).