Olive to grey-green, adults with pronounced frontal tubercle with high vertical brow.
Size : 130 cm
Habitat : In coral-rich lagoons and outreefs, 1-50 m. Largest species of the family, at least 70 kg. Feeds on living coral, bites off entire branches or noisily rams and breaks them of with tis frontal tubercle. Day-active, usually moves in fixed groups which collect early in the morning over a reef. Sleeps at night in groups in large crevices and caves. Rare and shy in the majority of regions.
Distribution : Red Sea (rare) and East Africa to SW Japan, Taiwan, Line Islands and French Polynesia.