VNS causes stimulation of the superior and recurrent laryngeal nerves and is associated with problems ranging from alteration of voice (66%), coughing (45%), pharyngitis (35%) and throat pain (28%) and hoarseness (very common) to frank laryngeal muscle spasm and upper airway obstruction (rare).
The giant manta is commonly found offshore, while the reef manta, as its name suggests, is found inshore near coral and rocky reefs. Manta rays live in the open ocean, swimming continuously through the water column instead of resting on the sea floor like other rays. Although much of their time is spent near the surface, they have been known to dive to depths of 100 feet.
Certain other rays may also possess tail spines. Some of the manta rays and eagle rays are so armed. The latter, forming the family Myliobatidae, comprise several genera found in warm and temperate coastal waters. They have very long, slim tails and, unlike other rays, have heads that project beyond the body disk.