We've already met the largest planteater to ever walk the Earth. But what was the biggest meateater? Spinosaurus is the largest carnivore to have lived, weighing in at almost 10 tons and 60 feet in length. It lived about 100 to 93 million years ago in what is now Africa. Carrying an impressive sail, a mere arch of the back would raise the sail to almost seven feet. It is thought to have survived by eating fish, though judging by its size, Spinosaurus could have easily hunted smaller dinosaurs. It also has the longest-known head of any dinosaur, measuring 6 feet.