What is a ray?
Rays belong to a group of cartilaginous fish called elasmobranches that also include the sharks. These ancient creatures have been on the Earth for more than 100 million years and lived during the time of the dinosaurs. Found in all oceans of the world, rays have flattened, disk-shaped bodies with enlarged, winglike pectoral fins. They also have a long, slender tail that most often has one or more razor-sharp, saw-edged, venomous spines that they use for defense.
Rays possess the following characteristics:
- Cartilaginous skeleton: Rays have no bones. Touch the tip of your nose and you will feel cartilage. The cartilage of the ray’s skeleton is hardened by calcium, especially the vertebral column. Red blood cells are produced in the kidneys and in an organ called the epigonal.
- Spiracles: Rays use these round openings behind the eyes to assist with respiration. Water enters the spiracles and exits through the gill slits.
- Five pairs of gill slits: Ray’s gill slits are on the undersides of their bodies.
- Dermal denticles: Derm means skin and dent means teeth. These scales, or “skin teeth,” are composed of the same material as teeth and help streamline and protect the ray.