How to get spino sails in Ark Survival Ascended the island (fastest method)
Spinosaurus dinosaur with large sail fin on back 1
It's thought that Spinosaurus' sail was likely a display structure to possibly attract mates. Some birds do a similar thing where males look all fancy but the females look a bit plain.
Methods of Farming Spino Sails? - General Discussion - ARK - Official Community Forums