Cetaceans are a group of marine mammals that include whales, dolphins, and porpoises. They are known for their streamlined bodies and adaptations for life in water, such as the ability to hold their breath for long periods. Cetaceans are warm-blooded and breathe air through blowholes located on the tops of their heads. These animals are highly intelligent and exhibit complex social behaviors. Many species communicate using a variety of sounds, and some, like the bottlenose dolphin, are known for their playful nature. Cetaceans play a crucial role in marine ecosystems and are often studied for their unique adaptations and behaviors.