Which of these aquatic animals is NOT a mammal?
Whales, dolphins, and porpoises share a common classification as mammals. These marine creatures are warm-blooded, give birth to live young, and nurse their offspring with milk. These mammals all have lungs and must surface to breathe air. In stark contrast, sharks are not mammals; they are fish. Operating as cold-blooded entities, sharks breathe through their gills, extracting oxygen from water, while whales, dolphins, and porpoises breathe air through their lungs. Sharks also exhibit diverse reproductive strategies, encompassing both egg-laying and live births without nursing their young with milk.
The correct answer is Shark.