Are you talking about the spikes that run down the back of the tail? If so then I believe the Retic is the only one that does not have them. All the other rays I have seen do. The brown rays tend to have a single row where tigers, flowers, and black rays have multiple rows. They are not capable of stinging with them just with the larger stinger. They say if you step on them the spikes on there tail can cut the bottom of your foot like a saw blade when the ray takes off. Have only heard that not witnessed.