Dogfish and thornback rays are closely related.

Rays – flat sharks

Anyone taking in the thornback rays and dogfish in the OZEANEUM’s children’s tank or Kattelgat tank will be surprised to hear that these seemingly very different animals are actually very closely related. The close relations between sawfish and sawsharks is quite clear; at first glance they are hardly distinguishable from one another.

Together with chimeras, sharks and rays form the class of cartilaginous fish. Unlike bony fish, they lack real bones and do not have a swim bladder. Their skin consists of tooth-like dander, known as placoid scales or dermal denticles. Their sexual organs are designed for internal fertilization and they have electroreceptors, sensory organs called the ampullae of Lorenzini. They use these to detect electric fields and temperature differences.

In order to survive on the seabed in addition to open water, some cartilaginous fish have developed different head and body shapes. The ray’s pectoral fins are completely fused to its body. This gives most rays a more flat shape, and they swim by moving their pectoral fins. Sharks, on the other hand, are more streamlined and propel their bodies forward using their caudal fin. The jaw, nostrils and gill slits on rays are located on the ventral and give rays bright, angelic facial features. With sharks, however, the nasal openings are located at the front of the head and the gill slits are on their sides.