Why Sharks get Creepier the Deeper you Go

[Music] there is one group of creatures that has dominated the oceans for 450 million years a time during which sharks have had the opportunity to adapt and diversify into an array of weird and wonderful species many like the well-known great white shark have adapted to life in the open ocean as apex predators at the top of the food chain but the deeper you go into the gaping void of the deep sea the more peculiar and otherworldly they become let's take a look at these fascinating yet often misunderstood inhabitants of the oceans [Music] when we think of sharks many of us picture them as mindless killers but sharks are far more remarkable than mere monsters they are highly specialized predators demonstrating an array of adaptations in order to survive the various habitats of the ocean near the surface pelagic sharks like blue sharks makos and great whites exhibit fairly similar features they are streamlined to allow for faster movement and bluish grey so that they can blend in with their environment [Music] but these sharks represent just the tip of the iceberg for lurking in deeper waters is a world of elusive mysterious and often gigantic shark species from the bioluminescent lantern shark to the parasitic cookie cutter shark that tears chunks from whales and dolphins to understand why sharks of the depths are so different to those at the surface we must find out what caused them to diversify in this way the evolutionary history of sharks possibly dates back to the late ordovician period 450 million years ago in the time that followed these primitive sharks evolved in a number of ways with one group of cartilaginous fish having diverged 420 million years ago to become the alien-like chimera relatives of true sharks but belonging now to a different classification by the early jurassic period 195 million years ago the oldest known order of modern sharks the hexanshiforms or six skill sharks had emerged it was now that they evolved slender fast-moving bodies and flexible protruding jaws allowing them to eat prey larger than themselves while many sharks we find in our oceans today have changed immensely since the jurassic the few that remain unchanged the living fossils appear peculiar in comparison most notably they have six or seven gill slits instead of the usual five found on most sharks [Music] this can be observed in the frilled shark with its slim eel-like body and snake-like head [Music] another member of this order the bluntnose sixgill shark has a single dorsal fin placed well down on its back as well as an anal thing features that are remnants from their ancestors of the ancient seas what's even stranger is the fact that many of these more ancient sharks including both the hexanshi forms and the squaloforms now seem to inhabit the deeper regions of our oceans [Music] a feature that is best explained when we take a look at their adaptations and the conditions of their world in the depths there is less dissolved oxygen present in the water this suggests that for six skill thrilled and seven kill sharks it is advantageous to have more gill slits so that they are more efficient at absorbing the oxygen they need so there is no cause for them to evolve to lose the extra slits contrastingly sharks that move to the shallows have no need for the extra slits so they lost them over time the large eyes of six skills is also an advantage allowing them to take in as much light as possible other deep sea sharks reflect light in a process known as biofluorescence the cat shark is one of such sharks possessing the ability to reflect blue light and re-emit it as green light in order to attract mates another feature that we observe is that the deeper dwelling sharks tend to be far larger the greenland shark for example grows to 24 feet or 7.3 meters long making it one of the largest sharks in the ocean larger even than the well-known great white shark this is due to the phenomenon of deep siege gigantism the tendency of deep sea creatures to grow to larger sizes than their relatives from the shallows being larger means they lose less energy as heat and in the nutrient poor depths becoming more efficient is the only way to survive this extreme environment the full video explaining deep sea gigantism can be found on our channel but in addition to being larger the greenland shark has also evolved to live its life in slow motion with its highly slowed metabolism it can go for very long periods of time without eating and is able to become the longest living vertebrate on the planet growing up to 500 years old at depths of 7 200 feet or 2 200 meters the feeding habits of deep sea sharks are quite different from shallower species [Music] while makos and great whites rely on speed and agility to hunt down fast moving prey sharks here must be opportunistic and depend largely on carrion at sunken whale corpses they use their serrated teeth as knives to soar and tear away the flesh another species the goblin shark has a flabby body and a large liver to allow it to remain buoyant in very deep water it is an elusive species as are many of the creatures that inhabit the deepest parts of the ocean [Music] in fact one of the largest shark species on the planet the megamouth shark was discovered for the first time as recently as 1976 it is a filter feeder preying on zooplankton at the surface during the night and returning to the depths during the day this behavior is known as diel vertical migration the synchronized movement of zooplankton and fish up and down the water column over a daily cycle [Music] overall deep sea sharks are understandably unique in the lightless high pressure and nutrient poor depths [Music] adopting more ancient adaptations such as more gill slits flabbier slow-moving bodies and larger sizes is advantageous it underpins a distinct difference between these deeper species and sharks of the shallows which have evolved differently in order to become smaller and faster the deep sea is a different world to the surface waters where food is plentiful and survival is less of a challenge for a predator out the brand new deepsea hub over on our website for more facts and footage about the deep sea [Music] you

Channel: Natural World Facts

Views: 4,000,403

Rating: 4.9289947 out of 5

Keywords: deep sea, mariana trench, top 10, sharks, deep sea sharks, shark attack, great white, great white shark, deep sea wonders, natural world facts, giant shark, megalodon, megalodon caught on camera, greenland shark, sleeper shark, frilled shark, goblin shark, goblin shark footage, shark documentary

Id: L0mxKh6CEss

Length: 9min 9sec (549 seconds)

Published: Tue Feb 09 2021

Reddit Comments

[u/Cockur]

Can we get a screen shot of the the video thumbnail without the text?

[u/greasedfish]

That shark looks how I feel.

[u/qnt0x]

that shark looks like my uncle, and that aint a good thing

[u/metalheaddungeons]

I hate that it has human eyes

[u/EveryRecording]

It has puppy dog eyes omg

[u/jgomez315]

had a few minutes to spare before sleep, so I watched and subscribed. thanks for the nightmares, friend.

[u/Dapper-Management349]

Goblin shark? My favorite, so weird and fascinating looking.

[u/Present-Extent-8073]

Why he look human....