It is that time of year to shuffle those feet as you enter the warm Gulf of Mexico waters. If you see beachgoers shuffling along and you wonder if perhaps they need some aid in walking or that they may be doing a funny dance, don’t worry, they are most likely doing the “stingray shuffle”! Frequent beach goers know to shuffle their feet in the sand as they enter the water to warn sting rays of their approach. The vibration of the shuffling sand is usually enough to make a ray move on to avoid getting stepped on.
There are two hundred species of stingrays, but two of the most common in this area are Southern Stingrays (Dasyatis americana) and Spotted Eagle Rays (Aetobatis narinari), which live year-round in the Marco Island waters. As Gulf water temperatures rise, they will move in closer to shore and beaches looking for small crustaceans (shrimp and crabs), worms or small fish to eat. Southern Stingrays are “benthic” (on the bottom) dwelling rays that cover themselves in near shore, shallow sand waiting to catch their next meal. Spotted Eagle Rays are “pelagic” (swimming) and are often seen in large groups “flying” in the water very close to the beach looking for the same type of prey.
Cousins of the cartilaginous sharks, stingrays have characteristics of flattened shapes, with long, spine-bearing tails and pectoral fins fused to their heads creating “wings” that allow them to seem as if they are “flying” through the water.
Southern stingrays are the color of the habitat bottom they live in – brown, tan to olive color with rounded, diamond-shaped bodies with a long, whip of a tail. The Spotted Eagle Ray is kite-shaped, brown in color with white and yellow spots and also has a whip-like tail. Both species have their gill openings and mouth located on the ventral side(or bottom side) of their bodies. The location of the ventral mouth allows easy capture of bottom-dwelling prey as the ray moves along through shallow waters and on the sandy Gulf floor. The spine on the tail is a modified dermal denticle (the type of scale that covers sharks and rays) that has venom-producing tissue. The venom is protein-based and can cause great pain, and rarely (if the ray is large enough) can cause death as it can alter heart rate and respiration in mammals. The sting is purely a defensive weapon, not how rays hunt or kill prey. Located on the tails makes it more effective for “striking” predators – the strike is an involuntary response rather than a conscious “attack”.
If you have the unfortunate luck of stepping on an unsuspecting stingray and do get struck by a spine, or worse, get a spine stuck in your foot, soak the wound area in water as hot as the injured can stand for at least 20-30 minutes (*the venom is protein based so hot temperatures break down the protein in about 15-20 minutes) and do seek medical treatment to clean the wound for any secondary infections that may occur.
So, remember its spring, shuffle those feet and avoid a painful spine in your foot!
Strange Stingray Facts:
- A group of stingrays is called a “fever”
- Stingrays give birth to live young called “pups” (While a cousin of the stingray, the Skate, reproduces by laying eggs in leathery, black casings sometimes called “mermaid purses”)
- The tips of the pectoral fins, or “wings” of stingrays, when they break the surface of the water, sometimes are mistaken for shark fins
- Ancient Greek dentists used venom from stingray spines as an anesthetic
- Organs behind the eyes are called spiracles and help stingrays breath while hidden, buried in the sand
Nancy Richie is a long time Island resident and Marine Biologist.