Analysis of parrotfish feeding biology describes three functional groups: excavators, scrapers and browsers. Excavators have larger, stronger jaws that can gouge the substrate, leaving visible scars on the surface. Scrapers have less powerful jaws that can but infrequently do leave visible scraping scars on the substrate. Some of these may also feed on sand instead of hard surfaces. Browsers mainly feed on seagrasses and their epiphytes. Mature excavating species include "Bolbometopon muricatum", "Cetoscarus", "Chlorurus" and "Sparisoma viride". These excavating species all feed as scrapers in early juvenile stages, but "Hipposcarus" and "Scarus", which also feed as scrapers in early juvenile stages, retain the scraping feeding mode as adults. Browsing species are found in the genera "Calotomus", "Cryptotomus", "Leptoscarus", "Nicholsina" and "Sparisoma". Feeding modes reflect habitat preferences, with browsers chiefly living in grassy seabed, and excavators and scrapers on coral reefs.