Size Comparison: Human, Elephant, Blue Whale - When we compare a human to the largest animals on Earth, the differences are staggering. An average adult human stands around 1.7 meters tall and weighs about 70 kilograms, with a heart roughly the size of a fist, pumping about 5 liters of blood through the body. Now place that next to the African elephant, the biggest land animal, reaching up to 4 meters in height and weighing as much as 6,000 kilograms. Its heart alone can weigh 20 kilograms and