 Despite not having a sting, the porcupine ray is capable of injuring humans with its many sharp thorns. It is reportedly bold and tolerant of being approached closely underwater. The tough, thorny skin of this ray, made into a form of leather called shagreen, had many historical uses. In particular, it was used to cover the hilts of various melee weapons, as its extremely rough texture prevented slippage during battle. For example, the Japanese deemed it the only species whose skin was acceptable for covering sword grips. The Malayans used it to cover shields. The skin was also used ornamentally, such as by the Chinese, who dyed it and ground down the thorns to yield a mottled pattern. The native inhabitants of Funafuti Atoll used dried portions of the ray's tail as a rasp-like tool.
