12 Shark Facts That May Surprise You

Author: Helen

Mar. 07, 2024

Sports & Entertainment

1. Sharks do not have bones.

Sharks use their gills to filter oxygen from the water. They are a special type of fish known as "elasmobranchs", which translates into fish made of cartilaginous tissues—the clear gristly stuff that your ears and nose tip are made of. This category also includes rays, sawfish, and skates. 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. The dried jaws of a shark appear and feel heavy and solid; much like bone. These same minerals allow most shark skeletal systems to fossilize quite nicely. The teeth have enamel so they show up in the fossil record too.

Scalloped hammerhead shark.

2. Most sharks have good eyesight.

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.

A night shark's green eye.

3. Sharks have special electroreceptor organs.

Sharks have small black spots near the nose, eyes, and mouth. These spots are the ampullae of Lorenzini – special electroreceptor organs that allow the shark to sense electromagnetic fields and temperature shifts in the ocean.

4. Shark skin feels similar to 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.

Nurse shark skin. Unlike most other sharks, nurse shark skin is fairly smooth.

5. Sharks can go into a trance. 

When you flip a shark upside down they go into a trance-like state called tonic immobility. This is the reason why you often see sawfish flipped over when our scientists are working on them in the water.

Tagging smalltooth sawfish, Florida Everglades.


Sharks have been around a very long time.

Based on fossil scales found in Australia and the United States, scientists hypothesize sharks first appeared in the ocean around 455 million years ago.

Grey reef shark.

7. Scientists age sharks by counting the rings on their vertebrae.

Vertebrae contain concentric pairs of opaque and translucent bands. Band pairs are counted like rings on a tree and then scientists assign an age to the shark based on the count. Thus, if the vertebrae has 10 band pairs, it is assumed to be 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. Determining the actual rate that the bands are deposited is called "validation".

8. Blue sharks are really blue.

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. In life, most sharks are brown, olive, or grayish.

Blue shark.

9. Each whale shark’s spot pattern is unique as a fingerprint. 

Whale sharks are the biggest fish in the ocean. They can grow to 12.2 meters and weigh as much as 40 tons by some estimates! Basking sharks are the world's second largest fish, growing as long as 32 feet and weighing more than five tons.

Whale shark.


Some species of sharks have a spiracle that allows them to pull water into their respiratory system while at rest. Most sharks have to keep swimming to pump water over their gills.

A shark's spiracle is located just behind the eyes which supplies oxygen directly to the shark's eyes and brain. Bottom dwelling sharks, like angel sharks and nurse sharks, use this extra respiratory organ to breathe while at rest on the seafloor. It is also used for respiration when the shark's mouth is used for eating.

Nurse shark.


Not all sharks have the same teeth.

Mako sharks have very pointed teeth, while white sharks have triangular, serrated teeth. Each leave a unique, tell-tale mark on their prey. A sandbar shark will have around 35,000 teeth over the course of its lifetime! 

Shortfin mako shark.

12. Different shark species reproduce in different ways. 

Sharks exhibit a great diversity 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.

Sharks & fish understanding is key to catching 101

 If you under stand them, they will bite..
To be really successful when trying to catch fish the more you understand how the fish lives, eats, sleeps,
the more you can target that fish. When I go fishin I do not go "fishing" I go Trout fishing, or Snook fishing.
just because I am fishing for that fish does not mean I will not catch other fish like say, Red fish while Snook fishing,
It simply means I will catch more Snook, I go to places which are likely to have Snook,
I use baits or lures that I know are better for Snook, I use Rod & reel match together which are better for fighting Snook,
You get the idea But every once in a while it is off to plan "B" because What I thought I was going to do did not work.
Here I am going to tell you things about fish which I think will help you under stand them, and be better more successful

Have you ever know someone who reminded you of a dolphin? I mean they are walking around but half of their brain is asleep?
Yes dolphins have to breath air So they just can not lay under water & go to sleep so they shut down half of their brain
Left side I guess and just swim along. Then after a while the left side wakes up and they shut down the right side,
This allows them to sleep & not drown. For most people it happens when on the cell phone & they drive into things.
Not as good of a result.

Sharks are another one in order to keep their blood pressure up and keep water going through their gills, they shut down half of their
brain at a time, A few sharks shut down their entire brain, but their spinal cord has it's own nervous system which is just though\muscle movement
to allow them to swim & keep breathing.

Sharks do not show up on a fish finder either, No you could have ten dozen Sharks under your boat and not one would show up.
That is because fish finder look for air pockets or bubbles in the water, if you want to have fun glue some fishing line to a ping pong balls and put a sinker on them
Now drop a bunch of them next to a reef, there will be a bunch of boats, all anchored there fishing for what must be a whole school of Moby dicks.
All it will take is one boat to go over and it will show up as the biggest school of monster fish you have ever seen.

Normal fish have swim bladders which have air trapped in them. the fish squeezes the bladder a little and they sink open or expand the bladder and they float a little
much the way a Submarine works. That is what show up and the depth finder, the bigger the swim bladder the larger the fish show up on your screen.

Shark do not have a swim bladder so they can not float, So in order to keep alive they must keep moving, It was thought they would sleep for very brief periods of time
and glide Thru the water, wake up swim & glide sleep again, But with the find that dolphins sleep half their brain at a time it is now thought that sharks do the same.

Some Sharks will lose over 30,000 teeth in their life time, The teeth are now replaced in rows just as one falls out another moves up to fill the space. It is though
that many Sharks live 25 years or so, But some like the great Hammer and other no one knows how long they will live, I guess that is why they get new teeth
all the time, what good would a 200 year old toothless Shark be. 

One last useless Shark tid bit, The term Card Shark actually came before the fish, The fish got it's name from the predatory nature similar to the Card Sharks of
Europe the German work was Schorck Villain Loan or Card Shark, who would have thought.


 Bull Sharks, Lemons, or Nurse Sharks
 can lay on the bottom still and breathe
 they do not need to move around to live, which is why 
 you will find them in the shallow waters
 of the Harbor or the flats & canals,
 Yes it is possible that an 8 foot bull shark
 could be living in your canal, Bull sharks
 have been found as far north in the
 Mississippi River as Illinois.
 So they can truly live anywhere,

Most Sharks prefer live food, as they are predatory creatures,
Some people think Dead bait is better, no it is just easier to use, it is much harder to use a live fish, than a dead one for bait.

 But Sharks do prefer Live, Often a Hammer Head will push or nudge something to see if it is live and therefore good to eat,
 possibly with a taste test Hammer Heads are much more discriminate eaters, than their Bull Shark Cousins.

If you are going to use a leader for Shark fishing how long should it be, A old rule of thumb would be a foot longer than the Shark you hope to get.
That is because Shark skin is rough, really rough, and just the tail of the Shark as it swims away from you rubbing the line, the tail can wear through 60 pound mono
in a matter of minutes, Hench the term I got Tailed by that Shark. So if your leader is a little longer the tail can not wear through it.

When you are choosing the bait to use any type of fish is good, But how big should it be, try to picture the mouth of the Shark you are trying to catch,
if the Sharks mouth is 4 inches wide and 3 inches high, and your bait is 6 by 6 inches, well you are going to get lots of runs and no Sharks. Match the size of your bait
again like the leader to the Shark. I use the fist rule a bait about the size of my fist should be good for up to a six foot Shark.

 Here is a clean release, flatten the barb "No Blood"

Now the most important thing if you are
 catching & releasing Sharks please flatten the barb
 of your hook flat against the shank,
 Sharks have a meaty mouth,
 and it is very hard to get a hook out with the barb,
 way too much damage. and circle hooks are too
 difficult to get out, So a simple "J" style hook with the barb flatten
 is easy to remove and you will not lose the Shark as long as you keep
 the line tight.
 what I like is if I have to cut the leader as happens
 if the Shark is to big to safely handle,
 Or I forgot my long hook remover, by using a flattened
  barb "J" hook it should fall out,
 Which it is not likely a circle hook would,
 One point to stress
 "If you are one of those people who let the fish run half way to Texas
 before you will set the hook, Please use a circle,
 the J hook is not for you.

 Oh and Barb-less hooks do not work, as there is no way to keep the bait on,
 much less the shark. When you flatten the barb it leaves a bump and that holds the bait and The Shark in place.
I hope these tip help you in you endeavors
Have fun out there Frank



A beautiful day, well yes I found one and took my Sister Pam and My Cousin Tracy out for a bit of Shark fishing. I had not checked the Tide so if I had known what the tide would be for an out-going tide I like to fish in the north end of the harbor around the 20 foot hole or Marker #1 if the tide is in-coming I like to fish south in the Harbor like the Pirate Harbor hole or by Cape haze, But I had not a clue so I went in the middle of it all between marker #5 and Marker #6 in line between Cape Haze and Burnt store, I figured if the tide was going out I would be chumming towards Boca Pass. If the tide was coming in I would be chumming the Harbor.

So we get to the Spot you should be east of the line between Marker #1 off Ponce Deleon park to Marker #5 off Cape haze as this is the line all of the big boats travel in and out of the Harbor lots of wake and when or if they would slow down it makes it even taller wake waves, So picture the line in your head, and stay a ¼ mile or so east of that, much safer. Once I am there I put out the Anchor and then the Chum Bag keeping the bag about ¾ the way into the water and then first line out is a med to med heavy Spinning rod an 8-15 or maybe 10 -20 pound class rod, With a bobber and a short AFW bleeding leader with a 5/0 hook 4 feet below a float, Now the float line or bobber line goes out first. The reason is I like to check the direction of the currant, looking at the water will not tell you really which direction the water is really going, but that float will, and I do not fall in love with the spot I anchor at first, highly likely I will move the boat at least once, after seeing which way the bobber is going. I want my chum to flow when I am here at the south end of the Harbor over the gravel bottom, I know the general direction the gravel bottom takes and that gravel bottom unlike the mud bottom in most of the Harbor holds a lot of bait. Small crabs, tiny bait fish, shrimp and other types of bait often the chum will get them excited enough about the food that they will come out and that really brings on the larger predators.
So After I cast out the bobber line I open the bait and pull another 30 or more feet of line from the reel and close the bait again, Now once the line drifts off with the tide I cast out a rod free line no sinkers or floats. This free line with just the leader and the bait will on a slow tide be right at the bottom, and when the tide picks up a little faster it will lift the bait off a bottom some, higher off the bottom as the tide moves faster, just like the way a piece of dead bait would drift along naturally.

See also:
Making Introductions


Now I have not caught anything on my rod that have a sinker on them, So I decided to up those to larger rods with a larger bait 9/0 or 12/0 hooks with 250 pound steel leader and a half of mullet or big chunk of Bonita. I think the smaller sharks are staying more off the bottom and it is the larger sharks that are feeding deep during the day while I am out. You can tell when the larger Sharks show up if you have been catching smaller sharks and the bite just stops. Well that is a very good indicator that the big ones have showed up. One of the few predators small sharks have is big sharks.

I like to eat sharks hay it is only fair they would eat me given a chance so, when I catch one I judge how big a shark I will keep my my cooler, Yes if it will not fit on the ice chest I let it go. Now you should understand I was raised on wonder bread and my food is refrigerated or frozen and meat left out in the sun or worse yet letting the fish hang on a stringer will just make it a bacteria factory and while I enjoy the shower curtain in our bathroom which has a map of the world on it, Very cool, I do not feel the need to be running in there ever 10 minutes because I let my fish spoil in the heat. Ice it down.


For hooks I always use J hooks for shark fishing with the barb bent over as to leave as much of a bump there as possible.
Circle hooks are too difficult to get out of the sharks mouth and if I happen to break off, a J hook with a bent down barb has the best chance of just falling out of the sharks mouth. And there is no blood all over the boat. Be kind bend it over. For some reason that don’t sound right, any way.
For bait and chum I have been just using the frozen stuff, I don’t get much time to go fishing and it has been working. So frozen sardines and or thread fins cut in half or if they are smaller size I put the hook through the head into the body threading the hook from front towards the rear and then cut up the bait just a bit so more smell is released. These are the tricks I used to get my Cousin Tracy her first sharks
this is where we went, and I will tell you the first hit will be 35 minutes after your chum is out and the first real bite should be 5 to 10 minutes after that. If you are there or any where Shark fishing I give it an hour no bites I am out of there. And always start with the 3 basic rigs, flaot line , free line and sinker rig. I always think I dont care how I fish. I care how I catch.
And try smaller rods with 15 or 20 pound test, leave the drag a ¼ turn looser then when I Snook fish, it is open water and out in the open it is better to have more line than heavier line with less yards, let that Shark run take your time bringing it to the boat. Who wants to grab a green Shark or I should say a shark that is not tired out. And last tip always control the head of a shark holding a shark by the tail will get you bit. A shark can pretty much bit it's own tail. Control the head.

Fishin Frank





Shark fishing is a challenge and to make even more challenging try from land,

It is a misconception that you need bigger, larger reels in a boat, when the truth is I use much smaller reels and rods fishing from a boat than I do from land based fishing. Why how could that be? Well, it is simple my boat can travel at 50+ M.P.H. I can follow that fish where ever it want to run to. OK most of the time the boat is at Idle, But one day I hope to have that 20 M.P.H. Chase out though the gulf. Now lets see a pier match that. So in other words I can use the boat to follow the fish, So I do not need as much line on my reel. And try and look as I might I have never found the starter for the pier it just stays put right there I can't even get it in gear. So in order to land a big fish from shore you need to have 2 to 3 times as much power and line in order to slow down and stop a big fish,

One of the biggest mistakes people make fishing from land or pier is to use very heavy line on a small reel. A smaller reel does not have the drag pressure to stop a big fish quickly so all you do is run out of line quickly. Once you are out of line the fish either jerks the rod from your hand or breaks off.


For most pier/land based fishing, I would like to have about 300 hundred yards of line, for fish up to 4 feet long add 100 yards for each extra foot of fish. The line will help you tire out the fish, the friction of the line being pulled through the water is tremendous, Line friction is what people used before reels had so much drag pressure. Even a 14/0 Penn reel as big as paint can only had maybe 25 pounds of drag pressure, this is back when drag washers were made from leather. There is a secret bit of information which most people don't know and that is that when using a conventional reel and fish fish takes out half of the line, the smaller diameter of line on the spool increases the drag pressure to about double so a 14/0 half full has around 50 pounds of drag. And that get increased the more line if pulled from the reel. So today with reels which can have 40 pound or more of drag pressure, once the line is half out that could be 80+ pounds of drag and so you wonder why the hooks pull out or breaks so often on big fish. I think you get it now.
We all want that once in a life time fight with a monster fish or shark where we almost get dragged off the beach and into the water. Which that part is not bad and really will not hurt the fish, causing damage to the fish is about how long the fight last.

So how long should you fight a fish lets say a shark. You can fight a Bull sharks almost twice as long as a hammerhead before you risk killing the shark a Hammer head 45 minutes is the longest you can fight or the mortality rate will reach as high as 75% of Hammers caught die after an hour fight, They just put too much into it.

The true definition of catch and release is to use heavy enough tackle to land the fish in a reasonable amount of time. But what is reasonable? That be the question.
Tune in same fish time same fish place for more on how to catch big fish from land hook rigs and tackle next month,


Fishin on windy days has become the new normal So when my old buddy Blake came to town with his two sons, at least we were lucky and the wind was blowing hard from the east north east. I say lucky as it is easier to hide from the east winds.

We started out heading to the east side. We stopped at mangrove point and idled back over the bar, we knew the water was deeper once you get across the outer sand bar and the fish like to hang out under the mangroves and with the tide falling that deeper trough should be the place. Well it was for one little Snook.



 How ever we did have a school of white bait swim right up to the boat. Blake could not stand it so he got out the cast net and smartly threw at the edge of the school. They looked pretty small and most were but we did get a couple of throw-able size to fish with. Blake caught an under slot Snook so after a half hour of no fish we continued our way down the east side, what we were looking for were islands which had deeper pot holes out in front of them. By deeper I mean 6 inches or more of added water depth.



anchor on the north east corner of an island. Where we could cast the back of the Island “east being the back and the north side of the island. Cover two side. With the wind at our backs. If we fished for 20 minutes and no fish I would let the boat drift to be along the north shore of the island where we could cast the front or west side of the island and if that did not work one more short drift to cast the pot holes out in front.

If that did not work we moved to the next islands by the 3 rd island we had caught a Couple smaller Snook a little red fish, A few Smaller mangrove snappers and a lot of needle fish.
The fish were caught by free lining, and using poppin corks.

The poppin cork did catch more fish this day than the free line ones did. And the needle fish just attacked any bait under a float, the most needle fish I have even seen in on the east side, weird.


So time to change tactics. Head headed out to the bar and noticed a bunch a lot of bunch of Crab traps well crab traps are baited to attract crabs and 2+2 fish eat the same stuff so that is a lot of chum so to speak and we started drifting along between the crab tarps and the Trout were there we caught several but only a couple big enough to keep and while the boys were fishing with white bait. It seemed the keeper Trout 16 inches or so were both caught on shrimp under the poppin corks and two Bonnet sharks hit the shrimp under a poppin cork with a Pink Rock Port rattler jig head instead of just a hoof. We that is what the Trout had hit as well.

So all in all not a great day but not a bad day we caught a fish about ever 15 minutes during the time we fish averaging it out.



I will say the small white bait was a bit better for the Snappers we caught and of the 3 Snook 2 on white bait 1 on shrimp as far as the Sea Trout 50/50 but bigger ones on the shrimp.

So the Fishing with the wind while is not easy as fishing with a light wind, you can find ways to use it to your advantage.






Fish on. Dad starts reeling in a fish,

 I go to reel in the other lines before the fish gets tangled up in them.
          too late,    
  I notice the wind not the fish blown the line from one rod across
 the other rod and the one in the next one and cluster,
           get out the line cutter and re-rig.

    Dad is fighting the fish one of the tangled lines is tangles with the one with the fish,

      So I get his line cut loose and he lands the trout,

         Just a bit too short.

 I will blame the 15 mph winds on that tangle.


 So we moved closer to an island to get out of the wind a bit, good idea right? Stopping just a couple islands north of Pirate Harbor and anchored the boat and then cast up close to the Island with one rod using a sinker on the leader with a live shrimp, The sinker was to keep it from moving away from the island.

 2Nd rod we put a float on
  and cast it in front of the island about 20 feet.

 where we knew it was just a bit deeper a slight trough.

The float would let the live shrimp move around the trough.

 Dad and I each free lined a shrimp out toward the open flat hoping to find Reds in the Pot holes.


Then Fish on Dad got a hit weird thing is the fish had not pulled the instead swam a little towards the boat then off to the side. Wrapping that line with the other two we had out. So he did not know the fish was hooked up. Until it was a tangled mess. I saw where the fish was headed and tried to get the lines in and what I should have done was reel in my line from the front of the boat, as while I started reeling in the last one the fish saw it's chance to make life really miserable and shot straight to the front of the boat and tangled that line as well. So here we are holding rods that are tied together with a huge knot in the middle and 4 lines going every where. Still a fish on. And yes it was a cat fish a 2 ½ pound Hard head cat-fish who decided to get even for any bad things I have said about them and we let it go after cutting the lines and hauling it in hand over hand. This trip was about tangles and busted lines the only two big fish on we had one wrapped around a crab trap and the other wrapped around another line and both broke off.
OK the fish won the first two round, so we switched up and only one rod for each of us we started drifting. And Dad with a shrimp and a split shot, me with a shrimp under a float. Fish on. Yes it was steady fishing and catching easy as you please.

My lesson of the day, One rod, one line when the wind or tide is really going fast. Two rods don't make a catch. I went back to Mark Twain saying “Put all of your eggs in one basket and Watch that basket”
So when you are out there keep in mind it happens to every body, We all lose fish our rods tangle and things can just go bad. We did catch quite a few Trout and a Shark even a couple smaller Snappers. And of course the Cat-fish but it was a day of what the heck, really?

Fishin Frank










12 Shark Facts That May Surprise You




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