Form and Function

       The spotted eagle ray has many characteristics that atDorsal view of A. narinari. Photo courtesy of Li Newton. tribute it to its fellow rays however, this creature has a few unique features that make it its own. The body, or disk of the spotted eagle ray, along with others of the Myliobatidae family range from a variety of different colors and also different sizes. Males and female disks are around the same size depending on sexual maturity. Females can be between 64 to 226 centimeters across and male sizes are between 97 and 190 centimeters across (Tagliafico 2012). Like in the picture to the right there are flaps similar to wings on either side of their main body structure. These are the fins which allow them to swim effortlessly and gracefully.

      Next to talk about is their amazing tails. A spotted eagle ray’s tail is nearly twice as long as their body. At the base of the tail are several spikes which are venomous and very dangerous. Though not as dangerous as one may assume. The venom within the spike is "140 times less noxious than scorpionfish...and 40 times less toxic that lionfish,"(Enzor et al. 2011). It has been observed that the venom is hardly effective against the spotted eagle ray's predators. Spikes were found lodged in the teeth of several sharks. To learn more about the interactions between the spotted eagle ray and its predators, go to the interactions page. Only in dire situations do the stingrays use their spikes for defensive maneauvers. They are more likely to use their stingers when two males are fighting for dominance during mating season (Enzor et al. 2011). An interesting fact about their stinger spikes; they can grow back! Lucky thing too, because the DNA extracted from the stingers skin tissues can be scrutinized under microscopes for genomic DNA to be isolated by scientists without doing any damage to the eagle ray itself (Janse 2013). DNA is looked under microscopes to find whether one baby is related to more than one dad.

      The spotted eagle ray's sense of smell is extremely important for juveniles since they are left on their own to watch out for predatory sharks. Researchers conducted a study to measure organs within the olfactory system to see if size was correlated with age. They measured the olfactory rosette, bulb, tract, and the telencephalon. The researchers discovered that the size of each organ increased in size as the disc width increased for each ray. It is necessary for baby rays to have identical organs compared to adult rays so there is a greater likihood that the juvenile will survive. The researchers also compared male to female size ratio for the olfactory systems and found little to no difference between each gender (Schluessel et al. 2010).

       The last thing to discuss is how the Aetobus narinari chew their food! Eagle rays behold inside their mouth a series of flat teeth that together form plates. The flat teeth destroy the shells of their prey. They also have taste buds, kind of. In the eagle ray there are only about 6 of these “buds” on the upper and lower part of the mouth. Along with tasting, these papillae do a good job of clearing out the shell debris before ingestion (Florida Museum of Natural History).


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