Summary
Marine mammals called cetaceans that breathe air and communicate using sound.
In depth
Baleen whales filter krill; toothed whales hunt with echolocation. Adaptations: blubber, streamlined bodies, and diving physiology with myoglobin-rich muscle. Social structures include matrilineal pods in orcas.
Marine mammals have adaptations for diving: collapsible lungs, high myoglobin and bradycardia. Whaling reduced populations, and moratoria allowed some recovery.
Key idea: cetaceans evolved from land mammals related to hippos.
Cetaceans are fully aquatic mammals with streamlined bodies, flippers, flukes, blubber and a blowhole. They are divided into baleen whales (mysticetes), which filter food with keratin plates, and toothed whales (odontocetes), including dolphins and porpoises, which hunt individual prey.
Toothed whales use echolocation: clicks are produced in nasal passages, focused by the melon and echoes received through the lower jaw. Baleen whales communicate with low-frequency songs that travel long distances. Diving adaptations include high myoglobin levels, a flexible ribcage and slowed heart rate. Whales evolved from land mammals about 50 million years ago, with hippos as close relatives.
Example: blue whales are the largest animals ever.
Frequently asked questions
What is Whales and Dolphins?
Marine mammals called cetaceans that breathe air and communicate using sound.
Which area of biology covers Whales and Dolphins, and how advanced is it?
Whales and Dolphins is one of the 54 topics in Marine & Environmental Biology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Marine Food Webs, Oil Spills, Deep-Sea Life.
Why does Whales and Dolphins matter?
Whale falls feed deep-sea communities.
Can you give an example of Whales and Dolphins?
Blue whales are the largest animals known, up to 30 m long.
What should I learn before Whales and Dolphins?
Whales and Dolphins is a Beginner topic, so no earlier topic is required. Other Beginner topics in Marine & Environmental Biology that pair well with it include Oceans, Ocean Zones, Plankton.
What topics are related to Whales and Dolphins?
The closest topics to Whales and Dolphins are Marine Food Webs, Oil Spills, Deep-Sea Life, Marine Genomics. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Whales and Dolphins?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Whales and Dolphins. To practise the whole of Marine & Environmental Biology, use the Marine & Environmental Biology quiz.
How is Whales and Dolphins different from Marine Food Webs?
Whales and Dolphins: Marine mammals called cetaceans that breathe air and communicate using sound. Marine Food Webs: Phytoplankton support zooplankton, fish and top predators, with energy lost at each level. Read both side by side and note what each one explains.
How should I study Whales and Dolphins step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Marine Food Webs and explain the difference aloud. Finally, take the Marine & Environmental Biology quiz and come back to this page for any question you miss.