Sharks do not have bones, instead, they have cartilage that makes up their skeleton. Sharks make some bone material for their teeth and fin spines but for the most part, they are made up of cartilage, the same soft flexible material that makes up the end of a human nose.
Sharks are an incredible animal that dates back hundreds of millions of years and they are extremely unique. One of the biggest questions people have about sharks, besides asking if there is a shark in the water, is if sharks have bones. Well, check out this guide to learn about sharks and if they have bones.
We provoke a shark every time we enter the water where sharks happen to be, for we forget: The ocean is not our territory – it’s theirs. – Peter Benchley
Do Sharks Have Bones?
A shark actually has 0 bones in its body. Their skeletal system is actually comprised of cartilage, like what we have in our ears. While they do still have a skeletal system, it is just made of a different material than most animals we are used to.
Sharks are categorized as Elasmobranchii animals, which is a subclass of cartilaginous animals called Chondrichthyes. Chondrichthyes is the classification of animals who only have cartilage instead of bones.
What is cartilage?
Cartilage is comprised of cells called chondrocytes, which create the cartilaginous material in our bodies that is rich in protein and elastin fibers.
Humans have cartilage in our ears, joints, on our ribs, and in our airways. It is extremely resilient and has elastic properties, making it strong and flexible. Cartilage is not as flexible as our muscles are, and it isn’t as rigid as our bones, yet it is crucial in human anatomy.
What Purpose Does Cartilage Serve in a Shark?
So, what is the purpose of a shark having cartilage instead of bone?
Sharks are pretty darn heavy animals and can weigh as much as almost 8,000 pounds. What is pretty interesting is that if a shark were to become beached it will end up suffocating because it has no ribs. So it essentially suffocates on its own body weight.
Because they are so dang heavy the cartilage actually reduces weight and allows them to have more energy to get around and move more efficiently. Cartilage is also very flexible allowing the shark a little bit more flexibility.
Like we said above, sharks are very interesting creatures. Let’s cover some of the most interesting parts of a shark’s anatomy:
Undoubtedly most of you have seen the mouth of a shark (just hopefully not up close). Sharks’ teeth are unlike other animals because they are attached to their gums, as opposed to their jaw. What that means is that sharks can “resupply” their teeth throughout their entire life. Like you can see in the picture above a shark has multiple rows of teeth that will just continue to pop up to replace older teeth.
To me, one of the coolest things about a shark’s anatomy is that their jaw isn’t connected to their skull. Their jaw is supported by something called tesserae, which are blocks of calcium that provides incredible support but is still light and flexible like cartilage. Most sharks only have one row of these tesserae blocks, but bigger species of sharks can have up to five layers. This makes their jaw incredibly strong and sturdy, making it easy for sharks to rip apart its prey.
Fins and Tail
Sharks typically have 8 fins that help them maneuver and swim. Unfortunately, shark fins are highly sought after because of the Chinese food shark fin soup. People will go into the ocean and catch sharks, cut their fins off, then throw the shark back in the water alive. Removing a fin from a shark makes that shark unable to swim, so the shark will sink to the bottom of the ocean and suffocate and die. Shark finning is a major issue that has caused quite a stir in the animal protection community and is actually prohibited in many countries, including the EU, Australia, Canada, Taiwan, The United States, and many other countries. The global hope is for shark finning to cease so that these sharks aren’t dying unnecessarily for 1 part of their body.
A shark’s tail allows them to swim through the water to move and catch food. To breath, a shark needs to keep moving for water to pass over its gills, so their tails also provide them life.
There are many different species of sharks, but some stick out more than others. Let’s cover 3 of the most recognizable species of sharks:
Great White Shark
Great whites are the monster of the shark community. They can be as long as 20 feet and weigh in at 2,500 pounds. A Great White’s lifespan can be as much as 70 years, but it has also faced some intense challenges.
After the movie Jaws came out some people began hunting Great White sharks and killing them because people felt they were dangerous. This phenomenon was dubbed the “Jaws effect” and many sharks died because of it. Obviously, this wasn’t an intended consequence but it did still happen.
- Can leap out of the water to catch prey such as seals
- Great Whites are responsible for the most shark attacks on humans
- They typically stay in shallow waters
The Hammerhead is one of the most recognizable sharks because of the unique shape of their head. These sharks are typically pretty peaceful towards humans but can be scary because they can be as long as 20 feet and weigh around 1,200 pounds. What is very interesting about Hammerheads is that they swim in schools with other Hammerheads, whereas other sharks are very solitary and independent.
- Primary prey is stingray
- There are 9 different species of Hammerhead sharks
- Lifespan is about 30 years
Goblin sharks are a very rare, and ugly, deep-sea shark. This species of closely resembles lifeforms seen millions of years ago and is regarded as an ancient animal. When catching prey its jaw will lunge out and snag its prey with its mouth (see the video below).
- Extremely rare
- Found mostly off the coast of Japan