Little Skate Locomotion

A little skate (Raja erinacea) on the prowl for dinner. The little skate is probably the most common skate for nearshore Long Island Sound. They are usually quite shy and rarely larger than 2' long. Like all other skates the little skate has two modes of propulsion - undulating its "wings" - sort of ripple from the leading edge to the rear of the highly modified pectoral fins. This is in contrast to the Manta and Eagle Rays with "flap" their pectoral fin "wings" up and down like a bird. Some skates (including the Little Skate) also have highly modified pelvic fins which they use to "walk" or "punt" along the bottom. The anterior lobe of each pelvic fin is highly modified into a three jointed "leg" ( called the crus or plural being crura) which the skate uses to push off from the sea floor then glides along for a short distance. By moving each sides curs alternately this form of locomotion can be quite fast and efficient. It is also thought that this "punting" does not interfere as much as undulating the pectoral fin with their electroreceptors which they use to locate prey. In this video you can see the modified crura emerging from trailing edge of the pectoral fins, especially as it moves away from the camera.

Category:

Pets & Animals

Tags:

• little skate
• crus
• raja
• diving
• wildlife
• science