Some people argue that a vegetarian diet can’t support a large life-form. They obviously haven’t met the blue whale (Balenoptera musculus), a massive creature that survives on plankton.Weighing in at 150 tons, the blue whale isn’t only the largest mammal but, in fact, the largest animal known. Its ability to maintain life on such a grand scale is aided by its oceanic lifestyle.In comparison, the bull African elephant (Loxodonta Africana) is the largest land animal, and it weighs a mere 12 tons.