Like many other species of ray, the Aetobatus narinari generally breeds in the summer months. The rays don't become sexually mature until about 4 to 6 years of age. Once maturation is reached and copulation has taken place, gestation usually lasts around a year. The duration of gestation is variant upon the water conditions however, and can be as short as 8 months if necessary. The mother ray then gives birth to an average of 1 to 4 pups(Pederson 2011).
 Spotted eagle ray. Image found at

The process of fertilization occurs when a female is a approached by one or, in some cases multiple, males. The male attaches himself the female using his tooth plate and grasps onto her fin. This usually results in wounds left on the females. The male positions himself under the female and inserts his clasper into the females cloaca. The process is understood to be relatively quick, usually lasting from 20-90 seconds (online guide trinadad uwi). Females have been known to undergo this as many as 4 times before fertilization is complete and gestation begins (Pederson 2011). The fertilized eggs gestate inside the mother similar to other large sea creatures like whales but instead of having a direction connection to their mother via umbilical cord or placenta, the eggs are instead fed by the yolk of their own egg. The pups enter into the water column at an average size of 17-35cm  upon delivery, sometimes after being discharged via aquatic breach by the mother to aid in the pup's hatching (Bester).

Due to their wide geographic range and consistent reproduction, the A. narinari is starting to come into question. The disconnection between these groups of rays has resulted in what scientists may think is a delineation of the species (Richards et al. 2009). The species has begun to show unique morphology dependent upon which ocean area they inhabit and seem to display no shared genes. Consequently, scientists are looking into possibly splitting the Aetobatus narinari into individual species and subspecies (Richards et al. 2009).


Here is a video showing the mating process of two Spotted Eagle Rays.


<<                                                             Go back to our Home page!                                                          >>