Pacu (IPA: [paˈku]) is a common name use to refer to several species of South American freshwater fish that are closely related to the piranha. They are mainly herbivores, but will also eat small fish, insects, and meat on fishing lures (see omnivorous). Their teeth, which may resemble human teeth, are used to cut through vegetation and crush seeds that fall into the water. Pacu and piranha are distinguished from each other by their teeth and jaw alignments; piranha have pointed, razor-sharp teeth in a pronounced underbite, whereas pacu have square, straight teeth in a less severe underbite, or a slight overbite. Additionally, full-grown pacu are much larger than piranha.