Documentary, Prehistoric Assassins - Ep1 Blood in the Water 2010
#AncientEarth #Documentary #Dinosaurs #Prehistoric #Evolutionary
#AncientEarth #Documentary #Dinosaurs #Prehistoric #Evolutionary
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00:00They were among nature's most successful experiments in advanced weaponry.
00:08Cleaver jaws, jet propulsion, armor plating.
00:12Their mouths are big enough that they could swallow a small child whole.
00:16Each creature was a predatory pioneer.
00:19There was a tremendous amount of carnage going on constantly.
00:24There's nothing like it in the animal kingdom.
00:26They perfected the tools for hunting, killing, dismembering, and devouring prey.
00:34And then they passed them on.
00:37Prehistoric assassins.
00:48What makes a predator deadly?
00:52The lethal weapon it uses to close the deal.
00:55And when nature perfects a weapon, it keeps it, even after the killer disappears.
01:04This process of recycling traits, called convergent evolution, is as old as nature itself.
01:11Ever since life exploded in the Precambrian period, the ocean has been a testing ground for predators looking to gain an edge on their prey.
01:25As time goes on, the most innovative designs for destruction become apparent.
01:38One of the things we see throughout the history of life on our planet is sort of this continuous arms race between predators and prey.
01:49Only at the very bottom of the ecosystem did you have plant eaters and that sort of thing.
01:56Everything else ate everything else.
01:58Three hundred and seventy million years ago, in the shallow seas of the Devonian period, one marine assassin stood out above all others.
02:09A new kind of jaw that packed one of the most powerful bites of all time, but what prompted this innovation?
02:24Armor.
02:25Armor.
02:26Most Devonian prey had it, including plated fish called placoderms.
02:31As soon as there were predators, animals evolved protection from those predators, some sort of armor or some kind of hard shell.
02:40They ranged from small armored organisms that were snuffling around on the bottom, feeding on detritus and things, up to the large apex predators like duncolosteus.
02:52This was the original jaws, a pioneer at using these revolutionary structures called jaws, which evolved 410 million years ago from bones in their gills.
03:04Jaws are weapons that open wide, allowing predators to attack and devour much larger prey, but a jaw can also be used as a hammer to help crack a shell or stun prey.
03:19A hammer is a handy tool, but duncolosteus had an edge on other jawed placoderms, one that made it among the most deadly predators of all time.
03:34So duncolosteus represents one of the first times that these predators have developed a means of actually breaking down a larger prey item.
03:42Once you can do that, you can start eating anything in your environment.
03:46And duncolosteus did.
03:48One of the largest of the placoderms, it grew to an estimated 20 feet in length and weighed as much as an elephant.
03:56Its back half was a mass of sleek, muscular tissue, and its fearsome 4-foot wide skull was made of bony armor plates.
04:05But duncolosteus' formidable advantage, its jaw, was enhanced by specialized plates in its mouth.
04:13Duncolosteus had very large tooth plates, dermal armor, but they were arrayed in these meat cleaver-like plates that were arranged in the jaws of duncolosteus that were used to crush and bite its prey.
04:27Duncolosteus' tooth plates appear to be primitive teeth, but they are not.
04:34They were built for shearing rather than what teeth do, which is chew.
04:40True teeth had already evolved in the throats of jawless fish.
04:44Powered by throat muscles, they chopped up prey for easy digestion.
04:49But duncolosteus' tooth plates were powered by its killer jaws, cleaving its prey to bits.
04:55Unlike the ripping bite of predators like tyrannosaurs, the force of duncolosteus' bite was generated by the shearing action of its cleaver plates,
05:05similar to the cutting power of a giant pair of scissors.
05:09In some ways, it's almost like its own experiment in how to make a jaw.
05:14Armed with this new experiment, duncolosteus crunched and chopped its way through the bodies of the smaller armored fish of the Devonian period.
05:24It was probably doing some slow cruising around these reefs looking for a shark or a smaller placater to feed upon.
05:37When it spotted a prey item, it would have then thrust that tail in a couple of rapid tail strokes, darting toward the prey.
05:52Once duncolosteus was close to its prey, it would snap its jaws open with lightning speed.
06:01And how fast they opened may have been just as critical to the kill as how fast they shot.
06:09But how do scientists figure out the jaw speed of a long dead predator?
06:15With a little help from its 370 million year old bones.
06:20Mark Westney and his colleague Phil Anderson studied a group of fossilized duncolosteus skulls.
06:27They custom fit them with foam rubber muscles and entered their muscle measurements into a computer model.
06:34And we realized that duncolosteus was able to open its jaws quite fast, something like a tenth of a second.
06:41Duncolosteus' jaw speed allowed something unexpected to happen.
06:48Suction, which pulled its prey towards it.
06:54Then, before the prey had time to escape, duncolosteus' cleaver jaws would make the kill.
07:03Upper and lower were able to slide past one another.
07:10And that's when that high bite force would have been activated to bite a piece off of that prey item.
07:17One of the characteristics of large predators is often that they'll disable their prey by biting a piece off and then consuming it.
07:24Very much like two meat cleavers chopping the prey in half.
07:33The structure of duncolosteus' jaws made him a master of dismemberment.
07:41Anderson and Westney determined the power of this predator's jaws after they discovered a naturally occurring lever system
07:47called a four bar linkage that powered its bite.
07:54This type of linkage is incorporated in heavy equipment like tractors.
07:58And it increased the strength of duncolosteus' jaws by a third.
08:04They actually had a rather robust joint on the back of its skull connecting to the rest of the body.
08:09This would have allowed its skull to literally move upwards.
08:13And we've hypothesized that as that skull moved upwards, it would have actually forced the lower jaw to move down at the same time.
08:23By their calculations, duncolosteus' jaws packed a 5,000-newton bite force.
08:30A 5,000-newton bite force would be like a 1,000-pound boulder sitting on top of a meat cleaver sitting on top of your foot.
08:39By comparison, the bite force of a human is as little as a couple hundred newtons.
08:45Duncolosteus' bite force was three times that of a great white shark.
08:51Duncolosteus' jaw produced the most powerful known bite force ever.
08:58For any fish, living or extinct.
09:04Though incredibly successful for millions of years, duncolosteus and all the other placoderms disappeared from the earth 360 million years ago.
09:16But the killing tool that duncolosteus pioneered, a powerful bladed jaw, has been recycled and can be found again and again in predators throughout time.
09:27There are a lot of birds whose bills essentially have razor sharp edges.
09:33There are certain turtles which have sort of the same kind of beak structure.
09:37These aspects of dental tool design seem to re-evolve over and over and over again because they're really effective at slicing meat.
09:46Powerful and effective weapons recur in nature.
09:51The jaw of duncolosteus is hardly the only example of convergent evolution.
09:56Take this ancient assassin that lived 100 million years after duncolosteus disappeared.
10:02Six-foot megalograptus, whose weapon was a barrage of tools that made it one of the deadliest assassins that ever lived.
10:11Megalograptus, the ruthless six-foot assassin that prowled the Ordovician oceans more than 460 million years ago, is the largest arthropod that ever lived.
10:27The monstrous ancestor of modern scorpions and spiders.
10:32But size was only one of its deadly traits.
10:37Megalograptus was a lethal Swiss army knife, capable of attacking prey any number of ways.
10:43Versatility was its weapon.
10:49Monstrous megalograptus had six pairs of specialized appendages.
10:56Legs for walking, paddles for swimming, an articulated tail for propulsion that was also spiked for fighting and trapping prey.
11:06Front appendages were lined with spikes.
11:09Finally, cheliceri dismembered prey into pieces small enough to shovel into its mouth.
11:16450 million years ago, the earth of the Ordovician era, covered in ocean, was an alien world.
11:26There were no mammals.
11:28There were no reptiles.
11:29There were no birds.
11:30There were no amphibians.
11:32It's primarily a world of invertebrates.
11:35This primitive ocean, filled with trilobites and mollusks, was terrorized by versatile, heavily armed predators like Megalograptus.
11:48And like a weapons system in battle, Megalograptus would have had all its tools ready for deployment.
11:56The attack started as soon as it spotted its prey.
12:00This animal had compound eyes, just like the eyes of a fly or other arthropods, composed of many, many tiny little lenses.
12:10And they're curved and probably provided three-dimensional stereoscopic vision.
12:16Though it could walk on the sea floor, it also had the ability to undulate its tail and swim towards its victim.
12:27Once in range, it had kill opportunities for devouring its meal.
12:40Megalograptus was a mobile trap with appendages that could engulf and imprison its prey.
12:46Unlike anything in any other eurypterids is the presence of these amazing spines on the appendages, long, sharp spines.
12:59These spines were jointed and strong.
13:03They probably could come together and hold something very effectively.
13:11But if its prey did escape, Megalograptus probably could have also used its spine as a sieve.
13:18It might have been a very good strategy for a predator to just plow into that mud and kind of rake it through,
13:27using the spines as a basket and then picking out the delectable items.
13:32Once it grasped its prey, Megalograptus' many arms began shoving the helpless meal towards its mouth.
13:42But instead of teeth, Megalograptus' last set of appendages were cheliceli, powerful pincers beside the mouth.
13:52They didn't chew the prey, but the little cheliceli underneath would start the chewing mechanism, start tearing it up.
14:02We're not sure exactly how those appendages would have been used to manipulate the prey,
14:08whether or not they would have torn the animal open to get inside the soft parts,
14:12or whether or not they would have simply just crunched it and digested it.
14:15And if the front pincers needed reinforcements to defend its dinner, the tail could swoop in.
14:24The three pincers of the tail most likely moved in and out, as well as the third one up and down.
14:32They could grasp together very effectively and hold something very tightly.
14:37I like to think of the idea of the tail bending up over the head like a modern scorpion
14:42and basically grasping something and flinging it away from attacking the front end.
14:53Megalograptus disappeared 450 million years ago.
14:59But its incredibly successful predatory body plan, its lethal Swiss Army knife array of weaponry,
15:05survives to this day, recycled and redeployed.
15:10It is thought that scorpions living on land evolved from marine eurypterids.
15:17Scorpions and spiders inherited Megalograptus's grasping and trapping tools,
15:22helping to make arthropods the most plentiful animals on Earth today.
15:30But Megalograptus, lethal as he was, wasn't the apex predator of his era.
15:37The only thing that could rip apart a six-foot sea scorpion was a 30-foot monster
15:43that shot through the ocean with its own brand of inescapable jet propulsion.
15:49Speed. It can be a killing tool as deadly as sharp teeth and powerful claws.
15:56450 million years ago, this gigantic hunter, 30-foot Cameroceros, dominated the Ordovician Ocean.
16:15It cruised the waters over what is now North America, Europe, and Asia like a primitive submarine.
16:25Encased in a protective shell for defense, this soft-bodied cephalopod had strong, flexible, squid-like limbs for grabbing prey.
16:34It had a large, complex eye and a sharp, powerful, beak-like mouth.
16:40But all of this was powered by some mighty plumbing, a jet propulsion system that allowed it to hunt down anything it wanted.
16:48Mighty Cameroceros' killing tool was this jet propulsion.
16:53You can imagine these very large cephalopods swimming quite agilely in the water column as big, huge telephone poles.
17:02A swimming telephone pole may be a little hard to imagine.
17:09But there is a modern cephalopod that provides insight into how ancient Cameroceros worked.
17:16This is a shell of a pearling nautilus, and it is the only modern cephalopod that has a hard shell.
17:28It's coiled, but otherwise it's very similar to our creature, which is basically a long cone.
17:35Point it at one end, open at the other.
17:38This part of the cone, which is called a phragma cone, is divided into spaces.
17:46The other end, where the animal was, the soft parts, is called the body chamber.
17:53The soft tissue looked and functioned much like its cephalopod ancestors.
17:59There would have been an animal here with lots of arms hanging out, prominent eyes probably,
18:05and a jaw mechanism, a big jaw mechanism.
18:12But how exactly do cephalopods like Cameroceros use jet propulsion to hunt down prey?
18:20There is a structure that comes out here that's a hollow tube,
18:25and the animal takes in water on either side of the body
18:28and squirts the water out this thing, which is called a hyponome,
18:32so this creature, if it were swimming, would squirt, squirt, squirt.
18:38They have a specific organ known as a syphuncle,
18:41which is used to control gases in their chambers of their shell
18:45that allows them to control their buoyancy,
18:47allows them to rise in the water column as well as to sink in the water column.
18:51Cameroceros' accelerating jets helped satisfy its big appetite by making it faster than its prey.
19:05Our creature was the biggest guy on the block.
19:08This is a tiny specimen, and you can see how long it is.
19:12They were so big they could mess with everybody else if they saw fit.
19:16To fill that big body up, one of its favorite meals was another super predator, Megalagraptus.
19:32Megalagraptus likely knew not to tangle with the huge predator,
19:36but Cameroceros pursued its victim.
19:52With its prey near, Cameroceros will deploy its many tentacles.
19:57When the animal is looking for food, it stretches out the tentacles
20:03as though it's trying to feel all parts of the environment.
20:09Eventually, one or more of the tentacles will touch the prey,
20:13at which point it quickly will surge forward and engulf the prey.
20:21Megalagraptus did not give up easily.
20:24But it would have been no match for Cameroceros' crushing beak.
20:33The beak of Cameroceros is similar to an upside-down parrot's beak.
20:42Very large Cameroceros would have been incredibly strong
20:46and would have probably had no problem crushing the hard exoskeletons
20:50of some of these arthropods.
20:54Though powerful and fast,
20:58Cameroceros went extinct roughly 450 million years ago.
21:05But some cephalopods must have survived,
21:08because today's squid and octopus all descend from a common
21:12half-billion-year-old ancestor.
21:14And not surprisingly, these modern predators possess the same jet propulsion
21:21that made Cameroceros such a terror.
21:26Cameroceros overcame its cumbersome bulk by developing a unique propulsion system.
21:31300 million years later, another massive assassin was also surprisingly maneuverable.
21:39It stopped, started, and spun with the help of four paddles.
21:43And its prey paid the price.
21:49The Jurassic era produced such an abundance of lethal predators
21:53that the oceans were a virtual stew of assassins.
21:56From sharks and rays to early crocodiles.
22:04Joining this deadly crew was a massive lyopleurodon,
22:07which patrolled the Jurassic seas 160 million years ago
22:11over what is now Europe and Russia.
22:13A killing machine, this maneuverable short-necked plesiosaur,
22:21was armed with seven-foot jaws lined with teeth as long as those of a T-Rex.
22:27But it was lyopleurodon's surprising mobility,
22:30drawn from its four muscular paddles,
22:33that made it such a deadly assassin.
22:36It had two distinct modes,
22:39cruising and turbo-burst killing speed.
22:43Both helped it cut through the water and close in on its prey.
22:48And at 30 feet and three tons, it didn't take no for an answer.
22:53It was the biggest and the baddest of the large predators in the Jurassic sea waves.
22:58There's nothing that lyopleurodon, as an adult, has to worry about.
23:01So lyopleurodon is going to rule the Jurassic seas in its time.
23:07The real unique thing about lyopleurodon is it flies with four wings under the water.
23:12There's no other known predator that's ever done that.
23:16But just how did lyopleurodon fly using its four paddles?
23:21One of the problems of working with fossils is the animals are dead,
23:24so they're just a ghost without everything else that goes with them.
23:27In his lab at Vassar College in upstate New York...
23:32Hello there, welcome to the biorobotics lab at Vassar College. Come on in.
23:37John Long breathes life back into lyopleurodon,
23:40with the help of plastic, circuits and batteries.
23:44With a robot, we can put meat and bones and brain back onto the ghost.
23:49I'll grab the flippers, if you guys will just pull her out.
23:52John dubbed his super predator robot, Madeline.
23:57All right.
23:58Roughly the size of a baby lyopleurodon, Madeline was equipped with four flippers.
24:03She was turned loose in the swimming pool to answer the question of just how lyopleurodon pursued its prey.
24:10If you look at otters, or you look at sea lions, or you look at turtles, all these critters have gone back in the water.
24:18They tend to, when they're cruising around, just use one set of flippers.
24:21The size and structure of lyopleurodon's flippers indicate that they were all being used for propulsion.
24:29But this is not the case.
24:31What we found really surprised us with robot Madeline.
24:36You're not swimming any faster, once you get up to speed, than you are with two flippers.
24:41So it looks like four flippers were key for maneuverability and acceleration, and not swimming fast.
24:50Behaviors that come into play when lyopleurodon hunts and kills.
24:54And with relatively limited variety among the many creatures that inhabited the Jurassic Oceans,
25:03lyopleurodon would have likely been forced to make a meal of similar plesiosaurs.
25:08It could not afford to be picky, nor could it expend more energy than it could get from its kill.
25:14No creature can.
25:16Energy matters in biology, right?
25:18So that's part of the logic behind saying, you know what, lyopleurodon, if they were smart,
25:23weren't cruising around with four flippers.
25:26They were just using two.
25:27So it's incredibly expensive to move through water.
25:32Lyopleurodon's eyes faced forward like most hunters, so that it could track prey.
25:39And once it got close, lyopleurodon was ready to kick all four flippers into gear.
25:46If you have four flippers, that means likely you're going to be good at hitting the turbo button
25:51and getting a quick burst of acceleration.
26:03Lyopleurodon would get all its flippers involved in thrusting, steering, twisting and turning,
26:10giving it a surprising amount of mobility.
26:12You just take that momentum you have as a big critter and transfer that into a really cool maneuver.
26:21And that's going to throw off prey.
26:24They don't expect something large and relatively slow moving to be maneuverable at the last minute.
26:30In the struggle, lyopleurodon would add another brutal advantage,
26:35massive jaws crammed with teeth.
26:37The teeth are very large. They're three or four inches long.
26:43The root of the tooth is actually much longer, almost three times the length of the crown.
26:48So not only are the teeth large, but they have giant roots that hold the teeth into the skull very tightly.
26:53It's not repeatedly biting something, it's just holding onto something and working those teeth into the body.
26:57Now once lyopleurodon has killed something, it has to break that carcass up and it probably did that the same way a crocodile would,
27:04by twisting around, biting off big chunks and then swallowing the chunks.
27:08A true sea monster, lyopleurodon dominated the oceans for five million years.
27:26Although there are no vicious predators quite like lyopleurodon swimming today's seas, there is an unlikely parallel out there right now.
27:41What's thought to be the best modern analog for plesiosaurs, and that's sea lions.
27:45Sea lions are mammals and their osteology, the shapes of their bones, are completely different than what you see in lyopleurodon.
27:51However, it's thought that the fin stroke that plesiosaurs used is very similar to what you see in sea lions.
27:57Convergent evolution recycles good ideas endlessly, but occasionally something extraordinary happens.
28:0580 million years after lyopleurodon, this bizarre killer evolved an extreme shape never seen in the ocean before or since.
28:15And this shape made it one of the ocean's most effective ambush assassins.
28:21In the battle for survival, predators brandish such terrifying weapons as teeth, claws and jaws.
28:32But even a long neck can be an assassin's tool when it's combined with a solid 10-ton body.
28:39Elasmosaurus was 45 feet long from tip to tail and lethal despite its small head and jaws.
28:54That's because it used its neck to attack out of nowhere.
28:57This neck was the longest of any sea creature that ever lived.
29:02Twice the length of a giraffe's with 10 times more vertebrae.
29:07Just one of many long necked elasmosaurs that dominated the ocean for 35 million years.
29:12During the late Cretaceous period, from 100 to 65 million years ago, 85% of the planet's surface was underwater.
29:26Monsters ruled what little land remained.
29:30But most of the action was taking place in all that water.
29:43The Western Interior Seaway, a shallow ocean that covered the middle of North America, was a violent one.
29:51The Western Interior Seaway was truly the most dangerous seaway that ever existed.
29:56There was a tremendous amount of carnage going on constantly.
30:00In the midst of this carnage, one creature stood out for its killing style.
30:05This is Elasmosaurus platyurus. It's the first Elasmosaur ever found, collected in Kansas in 1867 and 1868.
30:16It's also one of the largest of the Elasmosaurs that are known today.
30:20They were one of the longest, probably the heaviest creatures, swimming in the seas of the Cretaceous.
30:26There's nothing like it in the animal kingdom.
30:29Even, you know, when we're talking about the long necked dinosaurs that inhabited the earth about the same time,
30:35they only have about a dozen or more vertebrae in their neck.
30:38And compared to this guy with 72, there was really no comparison between what Mother Nature was doing here.
30:45But just what was Mother Nature up to?
30:49Over the 125 million years that plesiosaurs swam Earth's seas, new generations kept adding vertebrae to their ever-growing necks,
30:58ultimately reaching an unthinkable total of 72 in Elasmosaurus.
31:05More than half of its body was pure neck with a very small head.
31:09And that speaks a lot about its feeding strategy.
31:13A strategy that was the culmination of millions of years of evolution.
31:19Ocean-dwelling plesiosaurs first evolved from shore-dwelling reptiles roughly 235 million years ago.
31:28Most of the world is actually covered in oceans, so it represents a huge opportunity.
31:34Consequently, we've seen repeated re-invasions of aquatic or marine environments by animals that were originally on the land.
31:44Over millions of years, evolution re-engineered them for success in the marine environment.
31:50In many cases, what we've seen is that the limbs actually become expanded and actually become paddles, and the limbs become the major propulsive organ.
32:03A deliberate swimmer, Elasmosaurus propelled itself with four huge paddles, adaptations of its four legs.
32:12But when Elasmosaurus flew along in coastal waters, it was cruising for small prey.
32:21The skull is relatively small, the jaws are relatively narrow, and that limits the size of the maximum size of the fish to say something three or four inches in diameter, maybe 15 inches long.
32:34And so something as large as Elasmosaurus, weighing several tons, is almost going to have to eat continuously in order to fuel its huge body.
32:48Small-headed Elasmosaurus hunted only small fish.
32:52But small fish had developed a defense against predators, schooling.
33:01If one set of eyes is good for detecting a predator, then hundreds of pairs in a school should be even better.
33:09The idea of being one of many is a very effective predator defense system.
33:14And what we see is the predators that will actually evolve to deal with these schools of fish.
33:23This was Elasmosaurus' challenge.
33:26But how did something this large sneak up on a school of wary fish?
33:31Fish's eyes are basically looking up and forward, because they prey on things at the surface, too.
33:37And because of that particular feature, they have a blind spot below them.
33:43And that was just where Elasmosaurus would lurk.
33:49It could dive down in the dark and look up at its prey.
33:54And if there was a school of fish above it, it could easily recognize the silhouettes.
33:59Elasmosaurus' skin most likely was dark on its top side,
34:04camouflaging it to blend in with the depths.
34:08But its lethal weapon, its neck, allowed it to be in two places at once.
34:17The advantage of the long neck is that the body is 15 foot below where the head is,
34:23and would be basically invisible.
34:26The last three or four feet of the neck enabled the head to be moved back and forth
34:31in a way to grab the fish once they got close.
34:35Elasmosaurus would rise out of the gloom like a lever,
34:39popping its head into the school to pick off a few unsuspecting fish.
34:48Their teeth are interlocking.
34:49It's kind of a fish basket.
34:51So they'd grab a fish and swallow it immediately.
34:54They wouldn't be chewing.
34:55They wouldn't be tearing of flesh or tearing things apart.
34:58The whole fish would travel down its long neck and into a gizzard,
35:04a pouch containing stones the reptile had swallowed.
35:08That enabled them to grind up their food relatively quickly,
35:12and probably helped in digesting pretty rapidly,
35:15and again, fueling this big body to swim through the oceans.
35:19For millions of years, plesiosaurs' long necks made them virtually invisible and invincible killers.
35:29Only the global extinction event 65 million years ago,
35:35likely triggered by a massive asteroid impact, could finally end their stealthy ways.
35:40Elasmosaurus is the exception that proves the rule of convergent evolution,
35:48of nature recycling effective weapons.
35:53Today, there's nothing on land or in the oceans with a body plan like that of Elasmosaurus.
35:58Even plant-eating giraffes have only seven vertebrae in their necks,
36:06the same as humans and most other mammals.
36:11Swans' necks have the most vertebrae, topping out at 25,
36:16enabling them to reach places shorter-necked ducks can't.
36:20This predatory assassin hunted the seas alongside Elasmosaurus,
36:27swallowing its prey whole, but it was designed to gulp down fish almost as big as itself,
36:33gluttony as a lethal weapon.
36:38What do you do if you're a prehistoric assassin with a mouth as big as your stomach?
36:43If you're Zephactonus, you stuff yourself until you burst, literally.
36:51This monster's gaping mouth was its deadliest tool and its fatal flaw.
37:00Though it grew to be the biggest fish of its day, reaching lengths of 20 feet,
37:05Zephactonus was built for speed, with wing-like pectoral fins,
37:09a wide blade of a tail, and a narrow back end.
37:13It also had a big mouth full of sharp, oversized teeth.
37:18It hunted the North American seaways for 35 million years,
37:23success by any standard.
37:26But it was most notable for its outsized appetite to fill up that big mouth.
37:31Zephactonus ate the biggest fish it could possibly ingest,
37:34and it ate them whole.
37:35A swift and efficient predatory adaptation.
37:40Over time, it got larger and larger and larger,
37:43because it was very successful at what it was doing.
37:46But success clearly came at a price.
37:50There are at least 15 or 16 specimens now of large Zephactonus
37:55that died within a few hours, at most a day, of consuming a large fish.
38:01The mystery to this guy is the fact that so many of them die with a full stomach.
38:14Today, Zephactonus fossils are particularly well preserved
38:19in the ancient Cretaceous seabeds of western Kansas.
38:21They are the most common of the large predators found in the Kansas chalk.
38:27This is the Smoky Hill chalk.
38:30It's a sea bottom deposited 85 million years ago,
38:34at a time when most of the middle of North America was covered by an ancient ocean.
38:38It contains the bones, the fossils of some of the most dangerous predators of that time.
38:43It was a tough place to live.
38:46We've got about six foot here.
38:49We're looking at, you know, 13 to 14 foot Zephactonus.
38:53This is a big fish.
38:55Big fish.
38:57Their mouths are big enough, they could swallow a small child whole.
39:04Zephactonus' throat would expand as the mouth opened,
39:07courtesy of a series of small bones.
39:09This helped increase the volume of the interior of the mouth while swallowing prey.
39:15The lower jaw fit back inside the upper jaws when Zephactonus closed its mouth.
39:21Chances are it had a target of a certain size of prey animal
39:25that would give it maximum nourishment for a minimum risk.
39:30And that size for a 12 to 15 foot fish was a 4 to 6 foot prey animal.
39:34You would eat one fish, be done, and go away.
39:40Nobody knows how long it took Zephactonus to digest an intact fish.
39:45But this strategy was extremely efficient.
39:48It reduces the number of meals and the energy expended in hunting.
39:53They would eat one prey animal at a time and then slip into a period of very little activity
39:59until they needed to eat again.
40:02That was their very successful survival strategy.
40:08But why have some fossils turned up with a supersized meal inside them?
40:13Could their eyes have been too big for their stomachs?
40:18I think visual attack was an important part of Zephactonus
40:21because they really had very large eyes for the size of the animal.
40:25It was also very fast.
40:28And if it was quite a ways away from its prey,
40:31it could actually position itself in front of the prey.
40:34It would have been able to close in on its prey,
40:38a 5 foot gilligus with brutal efficiency.
40:43It would attack from below with that upward pointing mouth.
40:47It would be able to open it at the last minute.
40:50Too late for the gilligus to realize what was happening.
40:58The gilligus would literally be sucked into Zephactonus' mouth
41:04and at that moment be trapped by Zephactonus' teeth.
41:09The teeth are huge in relation to the size of the jaw
41:13and in relation to the size of the animal.
41:14After it sucked the fish in partway, those long teeth would hold it,
41:20would grab it and puncture it and in some cases kill it
41:24so that it wouldn't struggle so much.
41:26But why did this brutal attack sometimes prove fatal
41:30for the Zephactonus as well?
41:32From time to time, the prey animal was maybe just a hair too large
41:36and or too active and may have seriously caused the damage
41:39that killed the Zephactonus.
41:42Or maybe the Zephactonus was not fully armed
41:46at the moment it swallowed its prey.
41:48Maybe its teeth were in a middle replacement stage
41:51and they weren't able to stun it as much as it normally would have.
41:55So when that large prey fish was going down the gullet,
41:59it actually managed to do some serious anatomical damage
42:03to the internal organs of the Zephactonus.
42:05Whatever the cause of death, Zephactonus was a voracious hunter.
42:11The ability to consume large fish whole was the deadly trait
42:15that made this killer an apex predator.
42:19But despite its success, Zephactonus went extinct,
42:23along with most of the large predators,
42:26at the end of the Cretaceous period.
42:28Yet its design lives on.
42:30Today, a fish aptly named the black swallower uses the same killing tool
42:37that allows it to gorge on fish larger than itself.
42:40And like Zephactonus, this extreme form of predation also has its downside.
42:47Occasional death for the swallower.
42:49Super predators sit at the top of the food chain because of their specialized weaponry,
43:03honed by eons of evolution.
43:06The tools that made these aquatic hunters efficient killers still dominate Earth's oceans,
43:11even though their original owners are long gone.
43:15Recycled, these tools have simply been installed in later predatory models.
43:21Because nature wastes none of the weapons of its very best assassins.
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