A thornback ray's usual size is about 4-15lbs in weight and 3ft (91cm) in length. Its coloration is usually a molted gray, or a yellowish brown. The thornback ray has rows of hooked spikes on their backs and tails. The spikes are used for defense against predators. Thornbacks are rays, which are different from skates. The main difference is in their appearance. Rays have much shorter 'noses' than skates. Though both skates and rays look very like flatfish such as sole or halibut, there is no relationship between their two families. Thornback rays eat fish, but will also consume bristle worms, crustaceans, and octopus. Thornback rays compete for food with other thornback rays. They compete for food with each other for survival. White sharks eat thornback rays. The thornback rays avoid being eaten by use of their rows of spikes on their back and tails.

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Author: Bob J

Published: 04/2009

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Sources: http://findarticles.com/p/articles/mi_m0FDG/is_3_101/ai_107524531 http://www.marlin.ac.uk/species/rajaclavata.htm

Photo Credit: http://upload.wikimedia.org/wikipedia/commons/9/96/Raja_clavata_-_Gervais.jpg