Little Ray Stingray and Shark Book displayed at 50% of viewport width
July 2018 by V. R. Duin

FISHY FISH:
CARTILAGINOUS FISH
WITHOUT BONES OR SCALES

Sometimes when we trip or fumble,
Teamwork may just stop our stumble.
That's why we must always show respect
To help that comes as we least expect.
(“Little Ray & Shark Patch Things Up”)

spiracles
“Fishy Fish” expands “Little Ray & Shark Patch Things Up” to show differences between stingrays and manta rays and sharks. These cartilaginous fish without bones or scales, may have teeth and may have tongues.

Cartilaginous fish are made of cartilage. Cartilage forms the outside ear of people. It is in joints and other inside body parts. Human babies have more cartilage than adults. It is replaced by bone.


Sharks are ancient fish. They did not lose cartilage over their centuries on earth. They have no bones and they have no scales. Like bones, cartilage breaks and wears out, but it is harder for nature to repair.


Manta rays, Great White, Hammerhead, Mako and Whale sharks must keep swimming. If they stop, they sink. Most fish have swim bladders for up and down movement. They also may aid survival in dirty water.


Fish in the shark family have no swim bladders. Some sharks store fats and oils in their livers to make up for the absence. Rays and bottom-dwelling sharks have large, flat fins to control their level in water.


Fish have gills. Before birth, people have gill-like parts. Gills are outside the body. They are behind the eyes on the heads of most sharks. They are under the heads of stingrays, rays and some sharks.


The large number of slit openings into the gills of fish in the shark family is unique. Most stingrays and sharks have five pairs of gill slits. Each of these opens into one gill. Bony fish have one opening to their many gills.


Fish have pectoral fins. Rays do not swim like most other fish. Some rays swim with a wavy motion. Others flap their pectoral fins like bird wings. Most fish steer with their pectoral fins.


Hammerheads swim on their sides. Most sharks, electric rays and bony fish move with tail “caudal fins”. The dorsal fin keeps fish upright. It is small or missing in flat rays and sharks.


Sharks are the only fish that cannot go backwards. Pulled, they die. Rays move elegantly, except electric rays. The fastest ocean swimmers may be: Lamnid Sharks in GURPS.


Not all fish have teeth in their mouths. A stingray's mouth is under its body. A shark's mouth is in the front of its head. Manta rays also have front-facing mouths.


Sharks shed tens of thousands of teeth during their lifetimes. Divers and beachcombers often find them. Stingray tooth findings are rare. An occasional tooth may be shed and replaced.


Shark teeth grow in rows. As front rows wear out or fall out, new rows move forward to replace them about every two weeks. Tooth damage can be hastened by snacking on cans, tires and other trash.


Most fish have tongues or tongue-like parts. Stingrays and sharks have small tongues made of cartilage on the floor of their mouths. Bony fish have bony tongues called “basihyals”.


All fish can taste. Taste is sensed by the body surface of some fish. Catfish and saw sharks taste with whiskers, called “barbels”. Stingrays and Sharks have taste buds in their mouths and throats.


The nose holes of fish are called nares. They give fish a sense of smell. The nose holes of cartilaginous fish are under their bodies. The nares of a fish are not connected to the mouth or throat or used for breathing.


Hearing parts are inside. Some fish have ear parts with no outside openings. Others sense sound vibrations with lateral lines. Like sonar domes on vessels, sound locates and sizes up obstacles or targets.


Fish hear frequencies that people cannot. Fish can find their way with sound. They hear sounds over great distances. Learn more from DOSIT: What sounds can animals hear?.


Manta rays, whale sharks and most sharks have eyes on the side. According to Sphyrnid Sharks in GURPS have eyes on each end of their hammer-shaped heads. Angel sharks and most rays have them on the top of their heads.


Sight requires light. Acuity varies by species and specimen. Some fish need periods of light and dark. Others live in darkness. They can be blind. Fish that glow may be attracting mates or giving warning.


Bony fish drink and leak water. Water enters via their mouths and their gills. They have a pore to release urine. Stingrays and sharks do not drink or leak water. It comes from their food.


Most saltwater fish urinate via their gills. Sharks have a gland near the anus to discharge urea. Rays and sharks can store urea. All fish have kidneys to filter wastes.


Most fish have scales. Fish scales grow with the fish. Bumpy “denticles” do not get larger. More are grown to fill the space in a regular pattern in sharks and irregular in stingrays.


Denticles may repel germs. Sharklet Technologies, Inc. is creating bumpy plastic medical wraps to ward infection. The CDC warns about water contamination in: Healthy Pets, Healthy People.