Round rays are the most common and will grow to about three feet. The diamond and bull's-eye get slightly larger, somewhere in the neighborhood of four feet wide. The mechanics are such that the remaining section of free tail can squiggle violently to work the sting in deeper. The sting on a mid-size ray might be four inches long. Fortunately, the large adults with knife-like stings generally cruise through deeper water.
Most human encounters are with juveniles.
The mother stingray gives birth to about 12 live stingrays in the spring. Herein lies the formula for trouble. Literature suggests cleaning the wound with salt water, removing all membrane remnants possible and immersing the foot in water as hot as the patient can stand without scalding the skin. Care should be taken to avoid infection in the wound. If you're stung in Mexico and you can get to the Cruz Roja, the numbing shot they give works wonders, Diffin says.