These creatures are long lived, but the exact age is hard to measure; one study based on modelling gave an estimated age of a specimen of "Scolymastra joubini" as 23,000 years (with a range from 13,000 to 40,000 years), but due to changes in sea levels since the last glacial maximum, its maximum age is thought to be no more than 15,000 years, wherefore its listing of c. 15,000 years in the AnAge Database. The shallow water occurrence of hexactinellids is rare worldwide. In the Antarctic two species occur as shallow as 33 meters under the ice. In the Mediterranean one species occurs as shallow as in a cave with deep water upwelling (Boury-Esnault & Vacelet (1994))