Tuesday, October 4, 2011

Bull Sharks

"Well, I'm back," he said.

-----

Bull sharks today.

Bull sharks aren't, as I immediately assumed them to be, bull/shark hybrids, freely roaming both land and sea unchecked by natural predators.  In reality they have no bull parts, nor do they make the water-to-land transition very gracefully.  But they can live in both saltwater and freshwater.  Which means that, yes, there could be something dangerous swimming below your feet in that cloudy lake water.

Bull sharks are not the only saltwater species that can enter and thrive in freshwater, but they are easily the most intimidating.  In fact, forty-two other species among the subclass Eslamobranchii, to which bull sharks belong, can live in freshwater.  The way they manage this is through a process called osmoregulation, where the concentration of water in an organism's body is maintained despite changes in the external environment.  All fish undergo osmoregulation; bull sharks are just particularly good at it.  By controlling the concentration gradients of solutes in their bodies, bull sharks can ensure that the proper levels of water and solutes diffuse through them (by the way, this means that in freshwater bull sharks pee a lot).

I like a creature that knows how much salt it wants.

Here is an image of the geographic range of the bull shark:

The bull shark has been recorded approximately 2,600 miles into the Amazon River.  Now, to my American readers, I ask you, do you see the bit of blue on the map stretching up the Mississippi River?  The Mississippi is only 2,320 miles long.  Do the math.

A couple other things about bull sharks:

1) In Nicaragua bull sharks are known as "Nicaraguan Sharks," probably because Lake Nicaragua is one of their usual haunts.  I, personally, think it's a load of bull (pun absolutely intended) that Nicaraguans would be so presumptuous.

2) The bull shark's diet consists mainly of bony fish and other sharks.  (What is this world coming to?)  They also eat a variety of other marine life (including dolphins, how sad), birds*, and terrestrial mammals (by which I'm assuming Wikipedia means people).





*I've always wondered about those birds chilling on the water amid violent bloodbaths on Animal Planet.  I always assumed the sharks left them alone.  But now I want to shout at the screen, "Fly, birds!  Use your wings--they want to eat you too!"

15 comments:

  1. Now I'm gonna be afraid of lakes...

    ReplyDelete
  2. Sharks that eat other sharks? that's my kind of shark!

    ReplyDelete
  3. Replies
    1. yup, jaws is based off of the bull shark. Which did in fact attack several individuals in 1916.

      Delete
    2. uhhhh, no, the shark in jaws was the great white stupid, and in 1916 the great white killed those people, although i like bull sharks very much

      Delete
  4. These guys are the most dangerous sharks apparently because they can go where ever they want.

    ReplyDelete
  5. The shark in Jaws was a great white. Also a mechanical great white. Robot sharks... I shudder at the thought.

    ReplyDelete
  6. Thank you! Now I'm not going to the sea next week. /:

    ReplyDelete
  7. They are really spread around the globe

    ReplyDelete
  8. I wouldn't want to have a swimming lap with one.

    ReplyDelete
  9. Luckily there are almost none sharks here at Adriatic sea :P

    ReplyDelete
  10. Hі thеre to evеrу boԁy,
    it's my first pay a visit of this blog; this weblog carries remarkable and genuinely excellent stuff for readers.

    My page :: www.Dallasseocompany1.com

    ReplyDelete
  11. Just because they can swim 2600 miles into the Amazon does not equate to the fact that they could or are likely to come that far up the Mississippi. You have to take into account the fact that the Amazon is closer to the Equater than the Mississippi. Therefore, the colder water temperature that the Bull Shark would encounter in the Mississippi needs to be taken into account. I do believe, however, that there has been a confirmed Bull Shark sighting as far north as Southern Illinois.

    ReplyDelete

to prove that you're worth your salt.