How has life on the bottom changed the skates and rays?

The first obvious difference between skates and rays and more typical fishes is their shape. The skates and rays are bottom dwellers and they have developed this very characteristic flattened appearance. Let’s know more about how has life on the bottom changed the skates and rays?

The pectoral fins, which in other fishes are situated just behind the gill cover on either side, are in rays enlarged to extend right round the head, rather like a pair of wings.

By gently flapping these ‘wings’ up and down the skate or ray glides and along very close to the bottom with the minimum of effort. The tail is hardly used at all and so it is very thin and trials behind, perhaps helping to steer.

How has life on the bottom changed the skates and rays

Skate and rays, like the sharks, have a soft gristly skeleton made up of cartilage, unlike the more advanced bony fishes.

The skate’s eyes are situated on top of its head as you might expect in a fish living on the bottom. This habit has also meant the skate cannot breathe water through its mouth as other fishes do.

How has life on the bottom changed the skates and rays

The open spiracles behind the eyes of this ray are clearly visible.

If it did it would get a mouthful of mud and sand. Instead, water is drawn through two holes (spiracles) behind the eyes and passed ours through the gills. Some rays that live in open water, however, breathe like other fishes.

How dangerous is the stingray?

There are over one hundred kinds of stingray, widely distributed throughout the seas of the world. They all have longer and thinner tails than other rays and skates.

How has life on the bottom changed the skates and rays

Projecting from the top of the tail near the body end they have at least one but sometimes two sharp shines. These would be dangerous enough but the spines have poison glands, and stabs in the chest and abdomen have proved fatal on a number of occasions.

How has life on the bottom changed the skates and rays

When provoked the stingray can whip its tail around in a long, sideways thrust, or it can stab forwards over its head at its enemy.

What do skaters eat?

Living on the bottom the skate naturally feeds on the other animals it finds there-crabs, lobsters and oysters and other mollusks. It has strong crushing teeth to deal with these shelled creatures.

How has life on the bottom changed the skates and rays

To get at choice mollusks buried in the sand the skate will flap away with its pectoral fins and gradually work its way under the surface. It will then often sit there with eyes and spiracles above the surface.

You may like also:

Leave a Reply

Your email address will not be published. Required fields are marked *