The most curious feature of the fish belonging to the order of rays is that their body does not contain any bones. They are chondrichthyes, which means that their skeleton is entirely made up of cartilages. Another interesting characteristic of their structure is that their oral aperture is situated on their bottom side. Most rays prefer the waters near the coast and feed on molluscs and crabs, picking them up from the bottom. They lay eggs, attaching them to plants growing on the sea bottom. They do not take care of their offspring. Thornback rays have a poisonous thorn on the end of their tail, used for protection. The thorn is connected to the outlet channel of the poison gland and if the ray is attacked, it injects poison under the attacker's skin. The largest ray is the Devil ray or Manta ray, the width of which may reach up to 5 metres. It is totally harmless to humans, feeding on plankton and smaller shrimps.

Southern thornback
It prefers to stay on the sandy sea bottom. While eating, it hides under the sand so that only its eyes and its tail are uncovered. Just like the other rays, it also lays eggs but they hatch inside their mother's body and are live-born. The poison thorn of the young rays is still soft so as not to hurt the mother. African natives use thorn of the full-grown ray as knives and harpoons.

Guitar ray fish
Habitat: the southern part of the Mediterranean and in the Atlantic Ocean from Portugal to Angola. They feed on tiny animals living on the sea bottom, primarily shrimps and snails. Characteristics: they live in 10-60 metre-deep coastal waters. They can also be found in brack waters - semi-salty waters. They are easy to recognise by the long nose and the large eyes of 5-6.5-fold diameter. They live near the bottom and very rarely emerge to the surface. They are mostly found lying on or hiding in the sea floor. The back of the animal is sand-coloured with a black patch on the bottom side of the nose tip.