USA TODAY International Edition
Sharks are boneless, but not all species are created equal
There are more than 500 species of sharks swimming in the deep blue sea. The ocean’s apex predator has been around for a very long time with its ancestors dating back approximately 455 million years, according to the National Oceanic and Atmospheric Administration. ● Each shark species has its unique way of life and some differ drastically from others. So, does this mean that each shark is built differently as well? ● Here is what you need to know about a shark’s body, as well as other interesting facts about the fish.
How many bones do sharks have?
Sharks do not have bones. Sharks are elasmobranchs, meaning they are made of cartilaginous tissues.
Other elasmobranchs include rays, sawfish and skates. These types of fish are lighter than others since cartilage is about half the density of bone, according to Discovery UK.
Elasmobranchs’ low density helps with buoyancy and prevents them from sinking. Sharks have livers filled with low- density oils, further aiding buoyancy, according to NOAA.
Are sharks mammals?
Sharks are not mammals; they are fish.
Some sharks give birth by laying eggs, while others give birth to live young – these sharks are viviparous, as are humans. Viviparous sharks develop a placental connection to their babies, similar to a mammal’s umbilical cord. This leaves some sharks with “belly buttons” after they are born.
Lemon, bull, mako and blue sharks are among those that give birth to live young.
The remainder of sharks are oviparous, meaning they lay eggs.
What do sharks eat?
Most sharks feed on small fish and invertebrates, while larger sharks often eat seals, sea lions and other marine mammals, according to NOAA.
If you are wondering if sharks eat humans, it does not happen often. Although sharks have been known to attack humans, this is often due to confusion or curiosity. Sharks do not actively look to attack humans.