Although Basilisks develope crests in captive conditions . It's thought to be food related and how much territory they have , ie out in the field . The bigger the crest the more dominate older the male is . Although I've seen some females with pretty big crests on their heads , but no sails . I maybe wrong but I dont think in captive conditions the crests will ever get as large or reach full potential as opposed to how it could become if it were living on a rather large Phelidendron in Amazonia .