Bullhead sharks and bull sharks are both classified as sharks, but that is about it. Bullhead sharks are much smaller than bull sharks, which can grow to lengths of little more than 5 feet (1.5 meters), but bull sharks can grow to lengths of up to 11 feet (3.5 meters) or more. Bullhead sharks have more slender bodies and characteristic "horns" on their heads, whereas bull sharks have strong, rounded bodies.