Like sharks, rays have a cartilaginous skeleton. Although a few, like the eagle ray and manta ray, are free swimming, they have evolved a flattened body and most are bottom-dwelling. There are about 480 known species and representatives are found from shallow coastal waters to the deep sea, as well as in estuaries and in freshwaters.
Stingrays, stingarees and eagle rays have one or two formidable, serrated spines at the base of the tail. A stingray lashes its tail only as a defensive measure when it is caught, stepped on, or otherwise disturbed. Each spine, which is grooved to help the venom travel to the tip, is enveloped in a sheath which usually includes a venom gland at its base.
Tip of a 30 cm long stingray spine (Dasyatis).
Photographer: Dianne Bray. Source: Museum Victoria
Although the stingray venom can cause excruciating pain, the serrated spine itself may inflict a deep laceration which is often accompanied by a subsequent infection.
Smooth Stingray, Dasyatis brevicaudata
Photographer: Rudie Kuiter. Source: Aquatic Photographics
In southern bays and coastal waters, the Sparsely Spotted Stingaree Urolophus paucimaculatus and the Eastern Shovelnose Stingaree Trygonoptera sp. are extremely common, often resting during the day partially buried in the sand at wading depths. Care must be taken to avoid stepping on usually well hidden individuals.
Although primarily used to ward off potential predators, spines of large species like the Smooth Stingray Dasyatis brevicaudata, known to reach a length of 4.3 metres, can be dangerous weapons. At least one death in Victorian waters has been attributed to this species as a result of a spine being driven through the heart of an unsuspecting swimmer.
Edmonds, C. 1989. Dangerous Marine Creatures. Reed, Sydney.
Gomon, M. F., Glover, C. J. M. and Kuiter, R. H. (eds). Fishes of Australia’s South Coast. State Print, Adelaide.
Halstead, B. W. 1970. Poisonous and venomous marine animals of the world. Volume 3. US Goverment Printing Office, Washington DC.
Last, P. R. and Stevens, J. D. 1994. Sharks and Rays of Australia. Melbourne. CSIRO Publications: Melbourne.
Paxton, J. R. and Eschmeyer, W. N. (Eds). 2003. Encyclopedia of Fishes. 3rd Edition. Fog City Press, San Francisco.
Yearsley, G. K. 2002. Field Guide to Australian Sharks and Rays. CSIRO, Australia.