Stingray biology

The Stingray is any of a class of cartilaginous marine animals of the subclass Elasmobranchii, orders Myliobatiformes (rays) or Rajiformes (skates), found in both salt- and fresh-coastal waters, as well as some rivers, around the world.

Species/Families of stingray include the round ray, Bat Ray (Myliobatis californica), Manta ray, diamond ray, Southern Stingray (Dasyatis americana), Atlantic Stingray (Dasyatis sabina), Yellow Stingray (Urolophus jamaiensis), Blue Spot Stingray (Taeniura lymma), Big Skate (Raja binoculata), butterfly ray (Gymnuridae), Pelagic Stingray (Dasyatis Pteroplatytrygon violacea) and Cownose ray (Rhinoptera bonasus). There are also freshwater ray species in South America (Potamotrygon Sp.), Asia (Himantura Sp.), Africa, and Florida (Dasyatis sabina). Most species of stingray are neither threatened or endangered.

Rays swim with a "flying" motion, propelled by motion of their large pectoral fins (commonly referred to as "wings").

Their stinger is a razor-sharp, barbed or serrated cartilage which grows from the ray's whip-like tail (like a fingernail). It is coated with a toxic venom.

Stingrays do not "attack" aggressively, or even actively defend themselves - when threatened their primary reaction is to swim away. However, when they are attacked by predators or stepped on, the barbed stinger in their tail is mechanically whipped up, usually into the offending foot; it is also possible, although less likely, to be stung "accidentally" by brushing against the stinger. Contact with the stinger causes local trauma (from the cut itself), pain and swelling from the venom, and possible infection from parts of the stinger left in the wound, as well as from seawater entering the wound. It is possible for ray stings to be fatal if they sever major arteries, are in the chest or pelvic region, or are improperly treated. Their stingers are normally ineffective against their main predator, sharks.

Treatment for stings includes hot water (as hot as the victim can stand), which helps ease pain and break down the venom, and antibiotics. Vinegar or urine may or may not be successful in easing pain; neither cleans the wound properly. Other possible pain remedies include meat tenderizer. Pain normally lasts up to 48 hours but is most severe in the first 30-60 minutes and may be accompanied by nausea, fatigue, headaches, chills, etc.

Among marine animals, stingrays are most closely related to sharks. Rays are viviparous (bearing live young in "litters" of 5-10), while skates are oviparous (laying eggs, the casings of which look like shark eggs). Since their eyes are on top of their head, and their mouths on the bottom, they cannot see their prey, and instead use their sense of smell and electro-receptors similar to those of the shark. Rays feed primarily on molluscs and crustaceans, or occasionally on small fish; rays settle on the bottom while feeding, sometimes leaving only the eyes and tail visible.

Rays may be caught on a fishing line, using small crabs as bait, and are often caught accidentally; they may also be speared from above. They are edible but not normally preferred; small rays may be cooked similarly to other fish, typically grilled or battered and fried. It is rumored that in some cases circular cuttings from bat ray wings are substituted for scallop. While not valuable themselves, stingrays can damage shell fish grounds.

Viewing Stingrays

Stingrays are not normally visible to swimmers, but divers and snorkellers may find them in shallow sandy waters, more so when the water is unseasonably warm.

The Baltimore Aquarium has a large stingray tank where they may be viewed from above or below; many other aquariums exhibit rays.

In the Cayman Islands, there are a couple of dive sites (each called "Stingray City") where divers and snorkellers can swim with large southern stingrays and feed them by hand.

Stingray Families

• Suborder Myliobatiformes
  (Original author is not entirely sure about the order for the following families)
  • Narcinidae [narcinid rays]
  • Rhinidae [rhinid rays]
  • Rhinobatidae [guitarfishes]
  • Plesiobatidae [deepwater stingray]
  • Gymnuridae [butterfly rays]
  • Myliobatididae [ eagle rays ]
  • Hexatrydonidae [sixgill stingray]
  • Mobulidae [ manta rays ]
• Suborder Rajiformes
  (Original author is not entirely sure about the order for the following families)
  • Rajidae [skates]
  • Dasyatidae [stingrays]
  • Urolophidae [round stingrays]
• Suborder Torpediniformes
  • Torpedo rays
  • Electric rays

Taken from the Wikipedia www.wikipedia.org
http://en.wikipedia.org/wiki/Stingray