The green humphead parrotfish is the largest species of parrotfish growing to lengths of 4.9 feet and weighing up to 165 pounds. They are found on reefs in the Indian and Pacific Oceans. All bumpheads sport a large protrusion on their forehead which is similar in function to a pair of horns on a bighorn sheep. The largest males have the biggest bumps and will occasionally use them as battering rams around spawning time, smashing headfirst into rivals in an attempt to show their dominance and retain territorial and breeding rights. They can live to be 40 years old.