The sperm whale can hold its breath for two hours, has large lungs, and a specialized spermaceti organ that regulates buoyancy and may store oxygen.
Beavers thrive in water, holding their breath for 15 minutes to construct intricate underwater dams and lodges.
Sea cows, a type of mammal, can hold their breath for 20 minutes, enabling continuous underwater grazing.
The harbor seal can holds its breath for 30 minutes. They are skilled in hunting fish and invertebrates.
Emperor Penguins hold their breath underwater for 18–20 minutes. They can slow their heart rates when submerged, reducing from 120 beats per minute to four or six.