July 12, 2013
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snow shark’s chance in hell
friend: this is the book i got on sharks. it is a kid book about them but it has information i want to see if you agree with.
me: i only know about fossil stuff so i don’t know how i can help. but sure whatever, shoot.
friend: sharks can be found in all types of ocean and even fresh water such as the Mississippi river.
me: uh, it isn’t really like that.(she looks at me like a fisherman that has caught her fish)
friend: how so? what does it mean the river anyways?
me: well, ok the best way to think of sharks is by imagining the rain forest. you have the upper, mid and bottom canopies. you would be safe in saying that sharks persist in all of them. actually can survive in multi levels, by interchanging between the three. kind of like a snake in the amazon that lives in the trees. some don’t really even go to the ground. the whole life can work in the trees. same with sharks. the river , i am not sure if the Mississippi had any. at least not naturally there, doesn’t really make sense.
friend: why? it says it can live in fresh water like the Mississippi. (she shows me the first line first chapter of the book. to the side is a picture of a oceanic blue. beautiful shark).
me: well ok the way the fresh water thing works is like this. lets say there is a great flood of sorts. the river that empties out into the ocean is teeming with the potentially good source of food. some sharks will follow that river in. the one in jaws, the great white. it actually did go into the river system at the new jersey island. hunting for food, following the river in. i think two or three people lost their lives in that river inlet alone. as for the fresh water type, that is typically a bull shark. which doesn’t go north. it goes south. from the gulf of mexico. one year there was a few of them that somehow ended up the other side, at California. which aside from being unique enough began to attack swimmers. the first recorded one in the media was this incredible tale, about how a guy rescued his young niece from a 4 or 5 footer, then after getting her to shore went back out and beat the shark crazily to try and reclaim the limb the shark had bitten off. he managed to do that and she was rushed to the hospital and apparently it was all good timing, as she still has the limb. according to the media at the time.
friend: so it was a bull shark? that lives in fresh water? what about the great white you mentioned? how come it went up the river how did it survive?
me: in the fresh water you mean?
friend :yea if it is a deep sea fish like you described before, how did it survive?
my eyes blinked blankly for a few seconds. before i submitted to once again being tasked with explaining stuff about biology.
me: well, the only real difference between fresh water and salt is the sodium percentage. the shark lives in the ocean, where there is a over abundance of salt. so it doesn’t really store any in it’s tissue.whereas, fresh water fish, store tons in their tissue in an effort to make up for the deficient. it really has nothing to do with the breath-ability or spurious ability to go between the two water types. the great white just wouldn’t be able to live very long of a life span.matter of weeks may not be so bad.
friend: i see…
she points at a picture of the hammerhead shark. reading there is something like 150 or so species of shark. ‘i thought there was more’ she said.
me:’there is, sharks are a huge collective. one of the last remaining forms of cartilaginous fish still alive. i think there are only two more other lines. one is a lamprey i think and the other is like i think saw-fish. i cant remember if they bunch skates and rays into the shark one or not. but they belong too. dogfish are the oldest representation of sharks.i love them they are neat. they cover all over and one of the smallest fish is a dogfish.’..i pointed at the hammerhead picture. ‘that shark is a perfect example of the way sharks have evolved. like from where they came from and as a existing advancement from the original lifeforms. do you know why hammerheads have that shape? ‘
she made a few pretty intelligent guesses.
i smiled then explained.’no , they are almost like the go between skates and rays, the head has electric and motion sensing nerves along the ridge. basically it is like a metal detector at a beach. they go along the sea bottom, waving their head over the ground, trying to sense for prey under the silt. this is basically how sharks began, as the medium spot of the ecological food chain in the devonian. there was a massive predator fish at the time that basically owned top dog billing. so, you see, like other fish, the shark adapted a school form of protection. in order to look big, against the predators that preyed on them. the hammerhead is the only shark that still really demonstrates this ability. by travelling huge schools. though , they are pretty big fish, you can only imagine what they were against…’
she looked at me.’things against sharks? really?’
me: hell yea, the ocean during the dinosaur times was full of top notch hunters.sharks didn’t really get into the upper branch till the big rock did it’s thing. the competition before that was too much.actually, ironically it was the sea reptiles that had that whole scene under wraps. the moasaur and pleisasaur.elasmosaur..you name it. even the crocodiles had a good fix on things at that time. sharks were like nomadic hunters, almost like what i would call the cat version of the ocean. the movies you see of the shark frenzy, where you will see the reef sharks spiraling and chasing the prey object up is akin to the same feeding behavior you see in seagulls. however, what happened was, after the dinos died out and the Oligocene came in, there was really no competition left. only the perciformes or boney fish. who mostly stuck around the fresh water and eventually over took all forms of the cartilaginous types. the grouper is an example of one form that has managed to survive. but, by that time, like mid Holocene, we had a new comer, megalodon, which theoretically could still be around. as they found a fresh none fossilized tooth of one , while trawling the sea bottom a few years back. very exciting stuff really.
friend: there are dinosaur sharks still around?
me: well pretty much that is synonymous when it comes to sharks to begin with.there were some pretty bizarre forms at the beginning, but generally speaking, once a shark always a shark is pretty much the point of thumb. though, to be honest there is no real way of telling.
friend: don’t the fossils show that?
me: no, unfortunately, we only have their teeth. the cartilage didn’t fossilize. so it is all guess work.
she sat quiet then asked how do we even know what they looked like then?
me: well, look at the hammerhead’s tail, what do you see?
friend: well it is almost even like a whales tail only up and down.
me: right and what else? anything else? (she shook her head no) ok, i thumbed through the book finding a six gill shark. what do you see here? she commented that the lower tail fluke was smaller.
i flipped back and forth between the pictures and then explained.
see how the backbone ends in the middle of the tail of the hammerhead? that means this shark is pretty modern. maybe around the time of the advent of mammals. which is interesting, but anyways, see how the tail of the six gill has the backbone actually making up the top part of the tail but the bottom part is flesh? this is an example of ancient shark. dogfish show this tendency as well. hence they are one of the oldest forms of shark in existence, some skates have this and the angelfish, which is as close to a skate a shark can get without being an actual skate, has the same feature. there is also as you notice a different amount of gills on some of these then the modern ones. so going by this, we can assume that the length of the back bone as it reached the tip of the tail in some represented the size of the fluke. sharks are very adapted for the water, having never left the ocean for land. it isn’t hard to imagine what it would have looked like. even know, we have only the teeth, we can identify the teeth, then use this concept to re-image what it may have looked like. see that whale shark? it is modern, because of the tail. notice the spots? do you know what they are for? that is so it can look like a school of small fish.
she said: i thought they only eat plankton?
me:they do primarily but i have seen footage where one used that camouflage to lure a whole school of small schooling fish near it and it swallowed them all up.
she was silent. once a shark, always a shark i said.
we went through the book and i explained what i could. at the end i was frustrated, why don’t they tell the kids the stuff i know i asked. she said well they are just introducing sharks to kids, you know, i said, there is no point in not giving the details to little kids.what do they hope to achieve? information she said. i asked about sharks? or our stupid need to constantly misinform about them?
i said as long as they keep denaturing and misleading people and misinforming what chance do the sharks have?
