![using unwrella and stingray using unwrella and stingray](http://2.bp.blogspot.com/-h6kXcgmsuxg/U0S-47OmeZI/AAAAAAABB_0/ysuJ2wdifhA/s1600/How+to+use+LOD+-+Level+Of+Detail+in+3Ds+Max.jpg)
With the spiracles, they can draw water free from sediment directly into their gills for gas exchange. So the stingray switches to using its spiracles. This is efficient, but the mouth cannot be used when hunting because the stingrays bury themselves in the ocean sediment and wait for prey to swim by. Most of the time stingrays take in water using their mouth and then send the water through the gills for gas exchange. The respiratory system of stingrays is complicated by having two separate ways to take in water to use the oxygen. Stingray spiracles are openings just behind its eyes. Spiracles are small openings that allow some fish and amphibians to breathe. During mating season, some stingray species fully change their tooth morphology which then returns to baseline during non-mating seasons. Male stingrays display sexual dimorphism by developing cusps, or pointed ends, to some of their teeth. In general, the teeth have a root implanted within the connective tissue and a visible portion of the tooth, is large and flat, allowing them to crush the bodies of hard shelled prey. The teeth are modified placoid scales that are regularly shed and replaced. This type of suspensions allows for the upper jaw to have high mobility and protrude outward. Stingrays exhibit hyostylic jaw suspension, which means that the mandibular arch is only suspended by an articulation with the hyomandibula. The mouth of the stingray is located on the ventral side of the vertebrate. The stingray breathes though spiracles just behind the eyes when it hunts in seafloor sediment Jaw and teeth The status of some other species is poorly known, leading to their being listed as data deficient. As of 2013, 45 species have been listed as vulnerable or endangered by the IUCN. Stingray species are progressively becoming threatened or vulnerable to extinction, particularly as the consequence of unregulated fishing. There are about 220 known stingray species organized into ten families and 29 genera. Most myliobatoids are demersal (inhabiting the next-to-lowest zone in the water column), but some, such as the pelagic stingray and the eagle rays, are pelagic.
![using unwrella and stingray using unwrella and stingray](http://panoptesv.com/RPGs/animalia/chondrichthyes/Dasyatidae/stingray1.jpg)
The river stingrays, and a number of whiptail stingrays (such as the Niger stingray), are restricted to fresh water. Some species, such as Dasyatis thetidis, are found in warmer temperate oceans, and others, such as Plesiobatis daviesi, are found in the deep ocean. Stingrays are common in coastal tropical and subtropical marine waters throughout the world. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwater stingray), Urolophidae (stingarees), Urotrygonidae (round rays), Dasyatidae (whiptail stingrays), Potamotrygonidae (river stingrays), Gymnuridae (butterfly rays), and Myliobatidae (eagle rays). Stingrays are a group of sea rays, which are cartilaginous fish related to sharks.