Another interesting creature you might see swimming or snorkeling on St. John is a Stingray. Close to shore you are most likely to see the Caribbean Whiptail Stingray as in the photos, but if you venture further out or snorkel from a boat, you might also see a beautiful spotted eagle ray.
Stingrays have a flat body and one or more barbed stingers (modified from dermal denticles) on the tail, which are used exclusively in self defense. The stinger may reach a length around 14 in, and its underside has two grooves with venom glands. The flattened bodies of stingrays allow them to effectively conceal themselves in their environments. Stingrays do this by agitating the sand and hiding beneath it.
Because their eyes are on top of their bodies and their mouths on the undersides, stingrays cannot see their prey; instead, they use smell and electroreceptors similar to those of sharks. Stingrays feed primarily on molluscs, crabs, lobsters, crayfish, shrimp and occasionally on small fish. Some stingrays’ mouths contain two powerful, shell-crushing plates, while other species only have sucking mouthparts. Stingrays settle on the bottom while feeding, often leaving only their eyes and tails visible. Coral reefs are favorite feeding grounds.
Are stingrays dangerous? Do stingrays bite?
Stingrays do not aggressively attack humans, though stings do normally occur if a ray is accidentally stepped on. To avoid stepping on a stingray in shallow water, the water should be waded through with a shuffle. Alternatively, before wading, stones can be thrown into the water to scare stingrays away. Contact with the stinger causes local trauma (from the cut itself), pain, swelling, muscle cramps from the venom, and later may result in infection from bacteria or fungi.The injury is very painful, but seldom life-threatening unless the stinger pierces a vital area. In the worst case the barb usually breaks off in the wound, and surgery may be required to remove the fragments.
Fatal stings are very rare, but can happen, most famously in the death of Steve Irwin in 2006, in which the stinger penetrated his thoracic wall, causing massive trauma.