Sea of Sharks

Live every week like it's Shark Week

eduardo-:

Sharks, And Why They’re (Literally) So Awesome
We all know that Sharks (superorder Selachimorpha) are pretty much the peak of what nature has been able to muster in terms of killing prowess and perfect adaption to one’s environment. We also know that they’re also, at least in some species, amongst the largest non-terrestrial, non-mammalian creatures that’ve ever lived. The Whale Shark, (Rhincodon typus), a species quite regularly approaching 12 metres (40 ft) in length and around 20 metric tonnes (45,000 lb), is the largest extant fish species that’s left in the oceans.
But, what has made the Selachimorphs so successful throughout the years? Quite simply, they’ve had at our best estimates, 400 million years to work on it. By comparison, anatomically-modern humans came to be some 200,000 years ago, and behaviourally-modern humans have existed just a quarter of that time (50,000 years). So, right off the bat they’ve been doing it a very long time. Over that time, they have diversified into hundreds of species - around 360 of them – amongst eight different physiological Orders.
The kind we’re inclined to be most associative with as sharks are the ones most regularly shown in the media; these are known as the Requiems (family Carcharhinidae). Amongst these we find some of the most adept predators that have existed in any ecosystem, each with its own special skillset that allow them to capture prey in an almost effortless manner. For example, the Spinner Shark, (Carcharhinus brevipinna) lives up to its name almost worryingly well – it literally spins vertically through the water column (and inevitably the air) and captures prey as it goes.
What really sets them apart from other animals, and what makes them incredibly suited for their purpose is their sensory abilities. Their ability to physically pick up on the trademark makings of a meal is almost incomprehensibly good to us. Although many species have quite well attuned eyesight for aquatic species (the biological construction of their eyes is similar to ours), where they really come into their own is their sense of smell (which can be as good as one part per million in some species), and even more amazingly, their sensitivity to electromagnetic pulses. Food which is of interest to hunting sharks produce electromagnetic energy by the simple process of respiration and circulation, and these are able to be picked up by the Shark’s Ampullae of Lorenzini. These are jelly-filled organs which line pores around the anterior portion of the body, with the highest concentration around the forward parts of the head.
Despite all of this, they are pretty much all heavily in decline. As good as they are at killing other stuff - being an apex predator calls for it - we’re significantly better at the job (if you discount the approximately 60 attacks a year on humans, the majority of which don’t actually prove to be fatal). Shark Fin Soup, general fear, general lack of understanding, ecosystem destruction, harvesting for traditional medicine and liver oil… really, we’re doing our best to wipe these guys out and have been for a veeeeeery long time. It’s kind of sad when you think about it. They’ve been here 2,000 times longer and reached the epitome of what nature has yet mustered in all manifestations, and yet we fin them for soup? Really? They are awesome, we’re just assholes.
But not all Selachimorphs are even keen predators! The two largest, the previously mentioned Whale Shark, and the Basking Shark, (Cetorhinus maximus) are both pelagic filter feeders. They feed on planktons. As with Whales, it’s interesting to note that the animals which have by far the greatest physical size within the group are the ones which feed on the smallest creatures.
You only wish you could be cool as a Shark. But you probably won’t ever be. Not without a few hundred million years to work on it, anyway.

photo: http://www.yourstuffwork.com/2011/10/world-shark-attacks-increase.html

eduardo-:

Sharks, And Why They’re (Literally) So Awesome

We all know that Sharks (superorder Selachimorpha) are pretty much the peak of what nature has been able to muster in terms of killing prowess and perfect adaption to one’s environment. We also know that they’re also, at least in some species, amongst the largest non-terrestrial, non-mammalian creatures that’ve ever lived. The Whale Shark, (Rhincodon typus), a species quite regularly approaching 12 metres (40 ft) in length and around 20 metric tonnes (45,000 lb), is the largest extant fish species that’s left in the oceans.

But, what has made the Selachimorphs so successful throughout the years? Quite simply, they’ve had at our best estimates, 400 million years to work on it. By comparison, anatomically-modern humans came to be some 200,000 years ago, and behaviourally-modern humans have existed just a quarter of that time (50,000 years). So, right off the bat they’ve been doing it a very long time. Over that time, they have diversified into hundreds of species - around 360 of them – amongst eight different physiological Orders.

The kind we’re inclined to be most associative with as sharks are the ones most regularly shown in the media; these are known as the Requiems (family Carcharhinidae). Amongst these we find some of the most adept predators that have existed in any ecosystem, each with its own special skillset that allow them to capture prey in an almost effortless manner. For example, the Spinner Shark, (Carcharhinus brevipinna) lives up to its name almost worryingly well – it literally spins vertically through the water column (and inevitably the air) and captures prey as it goes.

What really sets them apart from other animals, and what makes them incredibly suited for their purpose is their sensory abilities. Their ability to physically pick up on the trademark makings of a meal is almost incomprehensibly good to us. Although many species have quite well attuned eyesight for aquatic species (the biological construction of their eyes is similar to ours), where they really come into their own is their sense of smell (which can be as good as one part per million in some species), and even more amazingly, their sensitivity to electromagnetic pulses. Food which is of interest to hunting sharks produce electromagnetic energy by the simple process of respiration and circulation, and these are able to be picked up by the Shark’s Ampullae of Lorenzini. These are jelly-filled organs which line pores around the anterior portion of the body, with the highest concentration around the forward parts of the head.

Despite all of this, they are pretty much all heavily in decline. As good as they are at killing other stuff - being an apex predator calls for it - we’re significantly better at the job (if you discount the approximately 60 attacks a year on humans, the majority of which don’t actually prove to be fatal). Shark Fin Soup, general fear, general lack of understanding, ecosystem destruction, harvesting for traditional medicine and liver oil… really, we’re doing our best to wipe these guys out and have been for a veeeeeery long time. It’s kind of sad when you think about it. They’ve been here 2,000 times longer and reached the epitome of what nature has yet mustered in all manifestations, and yet we fin them for soup? Really? They are awesome, we’re just assholes.

But not all Selachimorphs are even keen predators! The two largest, the previously mentioned Whale Shark, and the Basking Shark, (Cetorhinus maximus) are both pelagic filter feeders. They feed on planktons. As with Whales, it’s interesting to note that the animals which have by far the greatest physical size within the group are the ones which feed on the smallest creatures.

You only wish you could be cool as a Shark. But you probably won’t ever be. Not without a few hundred million years to work on it, anyway.


photo: http://www.yourstuffwork.com/2011/10/world-shark-attacks-increase.html