Sharks and Rays
There are more than 375 species of shark in the world, of which 90 are found in Australian waters. The 30 families of sharks can be divided into two main groups: bottom dwellers and mid-water sharks.
The main characteristics of sharks include:
- A skeleton made of cartilage
- 5 to 7 gill slits
- no swim bladder
- renewable teeth
- rough skin covered in small 'teeth' called denticles
- ability to sense electrical charges
Manta - the world's largest ray
Most rays differ from their close relatives the sharks in that their gills slits are located on the underside of their bodies, and their pectoral fins are greatly expanded and attached to their heads creating wing-like appendages.
A few species, like the manta ray, swim in mid-water, feeding on small fish and plankton.