The Wonderful World of Sharks and Why They Are Amazing
Let's talk about sharks! These often-feared but endlessly fascinating elasmobranch fish are characterized by a cartilaginous skeleton (and in the same group as rays, sawfish, and skates), five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Sharks play a vital role in maintaining healthy oceans. As an apex predator, they eat fish and help create balance in the food chain. Sadly, shark populations around the world are in rapid decline. These majestic predators face their most severe threat from the fin trade, overfishing, and other human activities.
We hope to give you a new appreciation and greater understanding of these ocean dwellers. Here are a few amazing facts about sharks to help give you insight into their underwater world and what makes them so unique. We think they are pretty cool creatures and hope you do, too!
If you want to see sharks up close during your visit to the Crystal Coast, be sure to head over to the North Carolina Aquarium at Pine Knoll Shores. It's not far from your Emerald Isle rental and makes for a great day trip full of education, exploration, and fun for everyone. (Please note that at the writing of this blog the aquarium is currently closed, but check their website or Facebook page for the latest updates and information).
Now, back to the sharks!
AMAZING SHARK FACTS
Sharks don't have bones.
Their cartilaginous skeletons are much lighter than true bone and their large livers are full of low-density oils, both helping them to be buoyant. Even though sharks don't have bones, they still can fossilize. As most sharks age, they deposit calcium salts in their skeletal cartilage to strengthen it. These same minerals allow most shark skeletal systems to fossilize quite nicely.
Sharks have excellent senses.
Sharks can hear sound underwater for miles and detect odors within hundreds of yards. Their feeding is mainly dependent on vision. Most sharks can see well in dark-lighted areas, have fantastic night vision, and can see colors. The back of sharks’ eyeballs have a reflective layer of tissue called a tapetum. This helps sharks see extremely well with little light.
Sharks have a sixth sense.
Sharks can sense pressure changes created by currents or movement up to 100 yards. Sharks have small black spots near the nose, eyes, and mouth—called the ampullae of Lorenzini—which are special electroreceptor organs that allow the shark to sense electromagnetic fields and temperature shifts in the ocean. They can also detect tiny electrical fields created by prey’s muscular movement. This ability is good only within a distance of inches.
Shark skin feels like sandpaper.
Shark skin feels exactly like sandpaper because it is made up of tiny teeth-like structures called placoid scales, also known as dermal denticles. These scales point towards the tail and help reduce friction from surrounding water when the shark swims. Paired with their torpedo-shaped heads, this makes sharks efficient, hydrodynamic swimmers who tend to maintain a cruise speed of about 5 miles per hour, but can have bursts of speed up to 23 miles per hour!
Sharks can go into a trance.
When you flip a shark upside down they go into a trance-like state called tonic immobility, often used by researchers when handling sharks to subdue them. Subduing them minimizes their struggling and reduces the possibility of injury. When the shark is gently turned on their back, it’s thought to disorientate them, causing them to enter the state. The shark’s muscles relax and their breathing becomes deep and rhythmic. When released, the shark snaps out of this state.
A shark's vertebrae might tell its age.
Vertebrae contain concentric pairs of opaque and translucent bands. Band pairs are counted like rings on a tree and then an age is assigned to the shark based on the count (ex: 10 band pairs equates to 10 years old). Recent studies, however, have shown that this assumption is not always correct. Researchers must therefore study each species and size class to determine how often the band pairs are deposited because the deposition rate may change over time.
Most sharks aren't blue.
In real life, most sharks are brown, olive, or grayish. There are a few exceptions, though. The blue shark displays a brilliant blue color on the upper portion of its body and is normally snowy white beneath. The mako and porbeagle sharks also exhibit a blue coloration, but it is not nearly as brilliant as that of a blue shark.
Sharks are silent.
Sharks do not have vocal cords and do not use audible sounds to communicate. Instead, they express themselves physically. Sharks communicate with body language which includes fluffing of the gills, a drop of their pectorals, the arch of their back, their position in the water column, and the angle of approach.
Sharks can lay eggs or bear live young.
Sharks are very diverse in their reproductive modes. There are oviparous (egg-laying) species and viviparous (live-bearing) species. Oviparous species lay eggs that develop and hatch outside the mother's body with no parental care after the eggs are laid. Viviparous species have shark pups which leave their mother's body fully formed, teeth and all.
Sharks don't really sleep.
At least, they don't sleep like humans. Since some species have to continue swimming to pump water over their gills in order to breathe—instead of falling into a deep sleep, sharks remain semi-conscious. Bottom dwelling sharks have a spiracle, which is an extra respiratory organ, to breathe while at rest on the seafloor.
There are 500 shark species worldwide.
Of the 500 shark species worldwide, fewer than 10% are considered dangerous or are known to have been involved in attacks. Some of the more common species are not considered dangerous to humans, such as the sand bar, nurse, silky, and dogfish. Other injuries and fatalities from ocean activities far outnumber shark encounters: drowning, jellyfish and stingray stings, spinal injuries, cuts from shell, and being caught in rip currents to name a few.
50 shark species are found in NC.
Of the 50 shark species found in North Carolina's waters, 26 species are found from within the continental shelf to near-shore waters, but are not present in the local waters year-round. Some move north and south, and others move inshore to offshore. Some species visit coastal waters based on water temperatures, food supplies and breeding patterns. Chances of encountering a shark in North Carolina waters are very low, but you can minimize risks by reading these tips.
*Source: NOAA Fisheries
WATCH THIS SHARKS 101 VIDEO
DID YOU LEARN SOMETHING NEW ABOUT SHARKS?
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