The largest animal to have ever existed on Earth is the blue whale (Balaenoptera musculus). Blue whales can reach lengths of up to 100 feet (30 meters) and weigh as much as 200 tons or more. These magnificent marine mammals are known for their immense size and are the largest known animals to have ever lived, even surpassing the size of the largest dinosaurs. Blue whales primarily feed on tiny shrimp-like animals called krill, consuming several tons of them daily during feeding seasons. While they face threats such as ship strikes and climate change, conservation efforts continue to help protect their populations.