One report speculates that southern stingrays may communicate using pheromones. It was observed that the birth of offspring attracts males, leading scientists to suspect that birth produces some kind of olfactory attractant that alerts neighboring males, perhaps arising from organic molecules produced in the female's cloaca. Since female southern stingrays are able to mate soon after parturition, these could be considered to be sexual pheromones. Males occasionally touch females before, and bite them during mating, which may also serve in some communicative capacity.
Like other elasmobranchs, southern stingrays are equipped with highly developed senses of smell. They also possess thousands of Ampullae of Lorenzini on their undersides, particularly concentrated around the head, which allow them to sense electrical field produced by buried prey. Elasmobranchs also have lateral lines for sensing vibrations in the water, and a well-develped sense of hearing. The eyes of southern stingrays are not likely to be useful in sensing prey, being placed on top of the head. However, they are still rather large and well-developed and are likely used to sense predators and other disturbances in the water above.
Communication Channels: tactile ; chemical
Other Communication Modes: pheromones
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical ; electric
Because southern stingrays are large elasmobranchs with relatively low reproductive rates and slow growth, they are at risk of overfishing. Currently, this species has no special conservation status. Populations near the United States appear to be healthy, but there is little information on the populations in other areas where fishing pressure is heavier.
Growing tourism also appears to be affecting southern stingray populations. This is illustrated by the case of “Stingray City Bar”. This species is normally active at night and is a solitary forager, but at this site it is found during the day (when tourist activity is high) and in close proximity with conspecifics year-round. The continuous supply of food keeps the stingrays in this area and causes alterations to their behavior. Another issue is the hand feeding of these wild animals with foods such as squid, which are not found in their natural diet. Long term feeding with these abnormal foods can negatively impact southern stingrays by affecting their health and mobility.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Fully-developed young are born soon after hatching from their egg capsules, which occurs inside the mother's body. Hatchlings resemble minature versions of their parents.
Development - Life Cycle: indeterminate growth
Southern stingrays are not known to be aggressive towards humans. Since the they are often found buried in the sand in shallow waters, it is easy to step on them. When stepped on, they will use their venomous spine in self-defense.
Negative Impacts: injures humans (bites or stings, venomous )
In developing countries, southern stingrays are an important food resource. Southern stingrays are also a large tourist attraction in coastal and island locations throughout their range. A popular tourist site for stingray interaction, “Stingray City Sandbar”, is located in the Cayman Islands. About 150 southern stingrays are found there yearly. The stingrays at this location are found during the day and in a very crowded space, where tourists can hand feed them. The venoms found in association with the spines of stingrays are currently being researched for possible applications in biomedical and neurobiological applications.
Positive Impacts: food ; ecotourism ; source of medicine or drug ; research and education
Southern stingrays act as predators of several marine fish and invertebrate species, as well as serving as prey to larger cartilaginous fish species (particularly hammerhead sharks). A commensal foraging relationship has been documented between southern stingrays and double-crested cormorants (Phalacrocorax auritus), which are common coastal birds ranging from North Carolina to the Gulf of Mexico. As stingrays excavate the substrate in search of prey, they often stir up fish. The birds dive in and swim behind the stingrays to feed on snappers and grunts, though this is only possible in shallow waters. This stingray foraging habit also attracts follower organisms, which remain near a host in hopes of finding food. Some observed follower organisms of stingrays include Carangoides bartholomaei, Caranx latus, Cephalopholis fulva, Halichoeres radiatus, Halichoeres dimidiatus, Dactylopterus volitans, and Lactophrys trigonus. Bluehead wrasse (Thalassoma bifasciatum) serve as mutualistic cleaner organisms for southern stingrays.
Mutualist Species:
Commensal/Parasitic Species:
Southern stingrays feed on multiple organisms throughout the day (more so at night), so they are considered to be continuous foragers and opportunistic feeders. One study found the stomach contents of a southern stingray to include prey from 15 families, in four phyla. Major prey were crustaceans, small fishes, and worms.
Animal Foods: fish; mollusks; aquatic or marine worms; aquatic crustaceans
Primary Diet: carnivore (Piscivore , Eats non-insect arthropods)
Southern stingrays are found in the the western Atlantic Ocean from New England to Brazil, with abundant populations in the Caribbean Sea, Gulf of Mexico, Grand Cayman Island, British West Indies, Bahamas, coastal Belize, and the southern coast of Florida.
Biogeographic Regions: nearctic (Native ); neotropical (Native ); atlantic ocean (Native )
Southern stingrays are a marine species and are generally found in shallow waters (about 2 meters deep) of bays filled with sea grass beds and algal fields.
Range depth: 0 to 53 m.
Habitat Regions: temperate ; tropical ; saltwater or marine
Aquatic Biomes: benthic ; reef ; coastal
Very little is known about the average lifespan of this species. In a single study, the oldest age recorded for males was 12 years. The oldest recorded female was estimated to be 13 years old.
Range lifespan
Status: wild: 12 to 13 years.
This species is an elasmobranch (a cartilaginous fish) in the superorder Batoidea. Batoid species have a broad, flat, disc-shaped body that is formed by the fusion of the dorsoventrally flattened body, pectoral fins, and the head. In southern stingrays, the body and pectoral fins are expanded to form a diamond-shaped disc, which is about 1.2 times as broad as it is long, with females generally being larger than males. The disc width of Southern stingrays raised in captivity ranges from 48 to 53cm in males and 75 to 80cm for females. In captivity, the maximum reported disc width for male is 80cm and for female is 150cm. Wild southern stingrays have reached a maximum disc width of 200cm and a weight of 97kg. The tail can be up to twice as long as the body, and carries a sharp, serrated, venomous spine that is used in defense. The gills are located on the underside of the body. The eyes are located on top of the head, which is elevated above the rest of the body. Due to its feeding habits and elevated head, southern stingrays have spiracles that enable them to take in water dorsally. The skin is covered with denticles, which are scale-like body coverings. Body coloration ranges between dark gray, green, and brown.
Range mass: 87.7 (high) kg.
Range length: 150 (high) cm.
Average length: 75-80 cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; venomous
Sexual Dimorphism: female larger
The main predators of stingrays are humans. Another predator of southern stingrays are great hammerhead sharks (Sphyrna mokarra). The shape of this shark’s head enables it to hold down stingrays while feeding on them. Stingrays will often bury themselves in the sand to avoid detection by predators, and will also use their venomous tail spine in self defense.
Known Predators:
Anti-predator Adaptations: cryptic
Very little is known about the mating systems of southern stingrays. However, one study was able to report observations based on a single female southern stingray mating with two males. The female was followed by the two males, with one male eventually biting and holding onto her pectoral fin. This male then positioned himself so that his pelvic region was curled toward the female’s urogenital opening (also known as the cloaca). The male then flipped upside down and thrust his pelvic region in a rapid sequence for 10 to 33 seconds. Following this, the male released his bite from the female’s pectoral disc. Females are able to mate again soon after giving birth
Mating System: polygynandrous (promiscuous)
Age at sexual maturity varies with the geographical region. In captivity, females were impregnated, and thus considered mature, at about 5 to 6 years. Males, on the other hand, were considered mature at about 3 to 4 years. Maternal size is positively correlated with the number of offspring, which can range from 2 to 10. Stingrays that are raised in captivity bear young biannually, while in wild stingrays, it is usually once a year. Breeding behavior has been observed in early September in the Grand Cayman Islands, and in late August at Bimini, Bahamas. Gestation period ranges from 125 to 226 days with a mean of 175 days.
Southern stingrays use both primary and secondary nurseries for the development of young. The primary nursery is a habitat where a female gives birth to her offspring, while the secondary nursery is habitat where juveniles reach maturity. Little is known about the specific locations of these nurseries and migration of the offspring between the two habitats. In Belize, Glovers Reef is a known primary nursery where adult southern stingrays only visit seasonally for mating or to give birth. Scientists caught juvenile southern stingrays during the months of May, November, and December at a depth of 10 to 20 m on nearby rocky reef surfaces, which is believed to be a secondary nursery.
Breeding interval: Breeding occurs annually in the wild, biannually in captivity.
Breeding season: Breeding occurs in summer to early fall, varying depending on geography.
Range number of offspring: 2 to 10.
Average number of offspring: 4.2.
Range gestation period: 125 to 226 days.
Average gestation period: 175 days.
Range age at sexual or reproductive maturity (female): 5 to 6 years.
Range age at sexual or reproductive maturity (male): 3 to 4 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; induced ovulation ; fertilization (Internal ); ovoviviparous
Southern stingrays are ovoviviparous (producing young by means of eggs that are hatched inside the body of the female), meaning that unborn young are protected by the mother due to developing inside her body. During early development, the embryo uses a yolk sac for its nutrition. After the yolk sac is absorbed, nutrients are provided by the mother through the secretion of histotroph ("uterine milk"). No further parental investment occurs after the young stingrays are born.
Parental Investment: female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female)
