00:00A piece of whale rib has recently been found in a North Carolina mine.
00:04Not a big deal, some might think.
00:06Hey, why can't a whale be a miner, right?
00:09But this fragment offers scientists a unique glimpse
00:12at the interactions between prehistoric sharks and whales
00:15from around 3 to 4 million years ago.
00:19The thing is, three tooth marks embellish the rib.
00:22That means that the whale was once badly bitten by an animal with a super-powerful jaw.
00:27But judging by the spacing between the tooth marks,
00:30and it reaches almost 2.5 inches,
00:33this animal could be a mega-toothed shark.
00:35I'm talking about the megalodon.
00:38Or it could be a different shark species, which was around at that time.
00:41The curvature of the shark's jaw shows that the animal was relatively small,
00:46between 13 and 20 feet long.
00:48Yeah, small.
00:49As for the whale, it seems to be the ancestor of a great blue or humpback whale.
00:54Researchers are amazed.
00:56You don't usually expect to find evidence of animal interaction and behavior
01:00preserved in the fossil record.
01:02After examining the sample carefully,
01:05they concluded that the shark must have gone away with a mouthful.
01:08But the whale had survived because most of the fossil fragment
01:12is covered with what is known as woven bone.
01:15It quickly forms in response to localized infection.
01:18Such bone isn't particularly strong,
01:20and later, the body remodels it into compact bone tissue.
01:23But it takes time.
01:26The presence of this bone means that the healing was incomplete,
01:29and the whale passed away 2-6 weeks after the unfortunate encounter.
01:33On the other hand, its demise could have been unrelated to the infection and injury.
01:38Only a handful of fossils show such kinds of interactions between ancient animals.
01:43You can often find bite marks on fossils,
01:46indicating where the animal passed away and its carcass was scavenged.
01:50But this fossil is one of a few examples that not only show a wound
01:54inflected by another animal, but also demonstrate that the prey survived.
01:59All fossils are exciting for paleontologists.
02:03Yes, they need to get out more.
02:04But some might look terrifying to regular people.
02:07For example, look at this picture of tentacle arms and octagonal-shaped heads.
02:12When it first appeared in mass media,
02:14internet users claimed that it was some ancient organism that had come from space.
02:18Others thought the story was fake.
02:21But in fact, both the picture and the fossil are real.
02:25The fossil is known as a mortality plate,
02:28a fossilized representation of a mass extinction event of one or several species.
02:33The fossil actually contains more than a dozen specimens
02:36of a type of marine organism called a crinoid.
02:40Despite their looks, crinoids were not plants but marine animals.
02:44This particular species lived deep underwater on the seafloor.
02:47Crinoids were related to starfish, sea urchins, and brittle stars.
02:52These creatures could attach themselves to the seafloor with stalks made up of flexible porous
02:57disks connected by soft tissue.
03:00The stalks were hollow, and that's where the animal's nervous system was located.
03:04Crinoids absorbed oxygen through thin-walled tube feet.
03:08The creatures usually reached the length of more than eight inches
03:11and had five arms lined with leathery-looking, tentacle-like structures.
03:15They fed on plankton and sloughed off organic material.
03:20Now, even though these fossil finds seem to be super exciting,
03:24few creatures in the fossil record confused scientists as much as the Tully monster.
03:29This curious sea creature sported a toothy, trunk-like snout and eyes splayed out on a rigid rod.
03:35But the most bizarre thing?
03:37It has been impossible to classify.
03:40Researchers have been considering a variety of organisms,
03:43for example, segmented worms, swimming slugs, and primitive eel-like creatures,
03:48since the monster was discovered in 1966.
03:51Recently, they have even tried to connect it to some species of jawless fish
03:56with a backbone-like structure.
03:57A team of scientists from Japan has used high-resolution laser scanners
04:02to examine the anatomy of Tully monster fossils in 3D.
04:06They concluded that the enigmatic fossil might be an invertebrate after all.
04:11And still, the true identity of the creature remains elusive.
04:15In the 1950s, amateur fossil hunter Francis Tully
04:18found a ghostly imprint of a torpedo-shaped organism
04:22with a huge tail fin in the Maison Creek fossil beds in Illinois.
04:26Tully had never seen anything similar to the torpedo structure.
04:30He took his find to Chicago's Field Museum of Natural History.
04:34Paleontologists working there were baffled as well.
04:37Since then, scientists haven't been able to determine
04:40where the creature fits on the phylogenic family tree,
04:43or where they should spend Thanksgiving.
04:46In 1741, an explorer and captain named Vitus Johansson Baring
04:51led an expedition to map the coast of Alaska.
04:53The ship he was on got shipwrecked on what later became known as Baring Island.
04:58And they got hungry.
05:00Half the crew survived thanks to the discovery of an extremely large sea cow.
05:05With the meat of these animals nourishing them,
05:07the sailors managed to build a small ship from the wreckage and return home.
05:11On their way back, a scientist who was among them
05:14spent his time documenting the animals and plants they had found.
05:17The sea cow was particularly interesting because without it,
05:21the crew wouldn't have survived.
05:23These animals were more than 26 feet long and weighed around 10 tons.
05:28All sea cows are a member of the order Cyrenia,
05:31marine mammals more closely related to elephants than cows.
05:35The scientists described them as having black skin,
05:38a small head, and stubby forelimbs.
05:41Those sea cows floated on the water's surface, munching on kelp.
05:44After the information about these animals became widespread,
05:48sea otter fur trading expeditions made use of that convenient depot and route.
05:53Sea cows were docile and could be easily hunted.
05:56Long story short, within 27 years after the scientists mentioned those animals,
06:01they were driven to extinction.
06:03But it's not the saddest part.
06:05The fossil record reveals a much deeper and darker history.
06:09Fossils of sea cows have been discovered all over the world,
06:13from Japan to Mexico.
06:15It means that the animal once thrived in the vast kelp beds around the entire North Pacific Rim.
06:21That small population discovered by the expedition
06:24was probably the last remains of a once much larger and way healthier population.
06:30More likely, aboriginal hunting had already reduced the numbers of these animals
06:34to near-extinction levels.
06:36And the final blow came from Western hunters.
06:39The living close relatives of those ancient sea cows are rarely hunted today.
06:43Still, they're under threat of extinction themselves.
06:47To some, this amazing fossil might look a bit disturbing.
06:51Slaves' lentils are fossils that belong to animals called nummalites.
06:56They lived and thrived in a warm, shallow sea,
06:58covering part of Egypt around 40 million years ago.
07:01The name nummalites hints at the fact that larger specimens resemble coins.
07:06And in Egyptian folklore, they're even referred to as angels' money.
07:11These creatures have a simple, single-celled structure,
07:14which contrasts with their super-intricate skeleton.
07:17Look at this series of spiral-overlapping worlds.
07:20Each world is divided into countless tiny chambers.
07:23Nummalites can grow to be 4 inches in diameter.
07:26And still, they are the fossils of single-celled animals related to amoeba.
07:31How and why do they grow to be so large?
07:34The reason could be their symbiotic relationships with other smaller organisms.
07:39In the case of modern species,
07:41such symbionts are tiny golden-brown single-celled algae called diatoms.
07:47The shells of nummalites are relatively transparent.
07:50And since they're flat,
07:51there's a large surface area for the light needed for the diatoms to photosynthesize.
07:56For some reasons, scientists are still debating about them.
08:00The presence of plant symbionts and animals dwelling in the sea
08:03encourages the growth of a calcareous skeleton in hosts.
08:07So, the gigantic size of the nummalites in Egypt
08:10could be due to their close relationship with symbiotic diatoms.
08:14Does that make sense?
08:16Fun fact!
08:17A species of nummalites evolved very fast,
08:20and their fossils change from one layer of sediments to the next.
08:23So, the limestone used for the pyramids of Giza
08:26are so packed with such fossils
08:28that it's known as pneumolytic limestone.
08:31This limestone also contains two kinds of nummalites,
08:35the smaller slave's lentils
08:36and the larger angel's money.
08:38But those are not different species,
08:40but rather different stages in the life cycle of a single species.
08:44That's it for today!
08:45So hey, if you pacified your curiosity,
08:47then give the video a like and share it with your friends.
08:50Or if you want more, just click on these videos
08:52and stay on the Bright Side!
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