Antarctic blue whales can also grow to approximately 33.5 meters (110 feet), although verified measurements vary between individuals. Despite their extraordinary bulk, blue whales survive primarily on krill. Their size surpasses every known dinosaur, making the biggest sea creature in the world also the largest animal in Earth’s history. Unlike the filter-feeding blue whale, the sperm whale is an active deep-sea hunter. It weighed 2,744 kilograms (6,051 pounds), measured 3.25 meters (10.7 feet) long, and spanned 3.6 meters (11.8 feet) between its fin tips.