The heaviest animal on Earth is the blue whale. Adult blue whales can weigh up to 200 tons (approximately 181 metric tonnes) and can reach lengths of over 100 feet (30 meters). These massive marine mammals primarily feed on small shrimp-like animals called krill, consuming up to 4 tons of krill each day during feeding season. Despite their enormous size, blue whales are gentle giants. They are found in oceans around the world and are known for their loud, low-frequency calls, which can be heard over long distances. Conservation efforts are ongoing to protect these magnificent creatures from threats like ship strikes and climate change.