Southern stingray

Appearance

The southern stingray is adapted for life on the sea bed. The flattened, diamond-shaped body has sharp corners, making it more angular than the discs of other rays. The top of the body varies between olive brown and green in adults, dark grey in juveniles, whilst the underside is predominantly white. The wing-like pectoral fins are used to propel the stingray across the ocean bottom, whilst the slender tail possesses a long, serrated and poisonous spine at the base, used for defence. These spines are not fatal to humans, but are incredibly painful if stepped on. The eyes are situated on top of the head of the southern stingray, along with small openings called spiracles. The location of the spiracles enables the stingray to take in water whilst lying on the seabed, or when partially buried in sediment. Water enters the spiracles and leaves through the gill openings, bypassing the mouth which is on the underside. Female stingrays can grow to a disc width of 150 cm, contrary to the smaller male stingrays that reach maximum size at 67 cm.

Behavior

The southern stingray is an opportunistic forager, feeding on small crustaceans, such as alphaeid, penaeid and callianasid shrimp and brachyuran crabs; mollusks, bony fish, and lancelets. It feeds by flapping the wing-like pectoral fins to disturb the sand and expose the prey. This bottom-dwelling species is often found singly or in pairs, except in the summer months when it migrates in schools to higher latitudes.

Habitat

The southern stingray is an opportunistic forager, feeding on small crustaceans, such as alphaeid, penaeid and callianasid shrimp and brachyuran crabs; mollusks, bony fish, and lancelets. It feeds by flapping the wing-like pectoral fins to disturb the sand and expose the prey. This bottom-dwelling species is often found singly or in pairs, except in the summer months when it migrates in schools to higher latitudes.

Reproduction

Mating stingrays are rarely encountered in the wild. During one rare occasion, the male was observed closely following the female, and then biting her before grasping the female’s pectoral fins with his mouth, and then copulating. It is thought that southern stingrays are polyandrous, as a female was observed mating with two males in quick succession. The southern stingray is ovoviviparous, a method of reproduction in which the egg develops within the female’s brood chamber. The pups hatch from their egg capsules inside the mother, and are born soon afterwards. In captivity, gestation lasted 135 to 226 days, after which a litter of two to ten young were born.