How Many Bones are There in A Shark's Body

Introduction

Sharks are members of the class Chondrichthyes' superorder Selachimorpha, subclass Elasmobranchii. Rays and skates are also members of the Elasmobranchii, and chimaeras are members of the Chondrichthyes. Sharks are an elasmobranch fish species distinguished by their cartilaginous skeleton, five to seven-gill slits on the sides of the skull, and unfused pectoral fins. Sharks resemble regular fish due to their fusiform body shape and the placement of their gill clefts on either side of the head. Sharks normally have thick skin that is drab grey in colour and is roughened by scales that resemble teeth, though there are some exceptions. Along with pointed fins, a pointed snout extending forward and above a crescentic mouth adorned with sharp triangular teeth, and a strong, asymmetrically raised tail, these characteristics are also typical of them. Sharks must constantly swim in order to avoid sinking to the bottom since they lack a swim bladder.

Anatomy of the shark

1. Teeth

Shark teeth are continuously replaced throughout life and are implanted in the gums rather than being attached to the jaw. Similar to a conveyor belt, many rows of replacement teeth erupt and grow in a groove on the inside of the jaw.

2. Skeleton

Compared to the skeletons of bony fish and terrestrial vertebrates, shark skeletons are quite distinct. Sharks and other fish that have cartilage, such as skates and rays, have skeletons consisting of cartilage and connective tissue. Despite having a density that is roughly half that of bone, cartilage is both flexible and resilient. In turn, less energy is used because the skeleton is lighter. Sharks have no ribs; therefore, they are readily crushed by their own weight when they are on land.

3. Jaw

Like those of rays and skates, sharks' jaws are not fused to their heads. The jaw's surface requires additional support because of its high physical stress exposure and need for strength (in comparison to the shark's vertebrae and gill arches). Large great white sharks have jaws that can have up to five layers. To absorb the force of hits, the cartilage of the rostrum (snout) might be pliable and spongy.

4. Fins

Ceratotrichia, elastic protein filaments that resemble the horny keratin found in hair and feathers, are soft, unsegmented rays that support the long, elongated fin skeletons. Sharks have an average of 8 fins. Because their fins do not allow them to move in a tail-first manner, sharks can only drift away from items that are immediately in front of them.

5. Tail

Because of the propulsion provided by the tail, acceleration and speed are shaped by the tail. Due to the different settings in which each shark species evolved, their caudal fin morphologies differ significantly. Sharks have heterocercal caudal fins, which typically have a bigger dorsal section than a larger ventral component. This is so that there is more surface area for muscle attachment due to the shark's vertebral column extending into that dorsal section. This enables these negatively buoyant cartilaginous fish to move more effectively. Contrarily, the caudal fin of most bony fish is homocercal.

Physiology

1. Buoyancy

Sharks lack the gas-filled swim bladders that bony fish have for buoyancy. Sharks instead rely on their cartilage, which is only about half as dense as bone, and a huge liver that is filled with oil that contains squalene. Up to 30% of their body weight may be made up of their liver. Due to the liver's limited efficacy, sharks use the dynamic lift to keep their depth while swimming.

2. Respiration

Sharks' gills allow seawater to pass over them as they draw oxygen from it like other fish do. Shark gill slits, in contrast to those of other fish, are exposed and are found in a row below the head. A modified slit known as a spiracle located just behind the eye assists the shark in breathing in water. It is especially important to bottom-dwelling sharks.

3. Thermoregulation

The majority of sharks are poikilothermic, or "cold-blooded," meaning that their internal body temperature is the same as their surrounding environment.

Conclusion

• No bones can be found in the shark's body.

• The shark's entire body is composed of cartilage.

• Sharks are not mammals since they lack any of the traits that define a mammal.

• They don't even have warm blood.

• However, they do belong to the fish family.