Before venturing into the warm waters of the Gulf of Mexico, swimmers are frequently greeted by signs urging them to "Do the stingray shuffle." These words of advice are intended to enable beachgoers to enjoy their outing, and avoid the painful, sometimes serious, injuries that can result from stepping inadvertently on bluntnose stingrays.
The sand-colored bluntnose rays, averaging about 6 inches across their body, are normally not aggressive. They bury themselves in shallow waters near the shore as protection, and attack only when threatened by a large predator, such as a human foot coming down on top of them.
By shuffling their feet, bathers usually startle the rays and send them into deeper waters. Young rays are considered the most dangerous, because they haven't learned to recognize humans and take evasive action. Mature rays usually stay out of harm's way in deeper offshore waters.
The ray's stinger is on the spine of its tail, near the base of its body. It's made of dentin, a hard, bony substance similar to teeth, and is covered in skin. The toxin the stinger secretes tightens the small veins around the wound. The sting paralyzes small fish that rays feed on. It can stop the heart of a small dog. It is potentially fatal to people with heart or respiratory problems.