Hyaenodonts: The Razor Jaws
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- Опубліковано 12 вер 2024
- (Sorry about the quality of my voice in this video; I've just recently had the Centaurus variant of Covid and I'm still recovering from it!) Emerging rapidly after the K-PG extinction event in Europe, they went on to colonize Africa, Asia and North America by the end of the Paleocene. Early forms were generally quite small and Viverrid-like, being fairly minor carnivores in ecosystems dominated by Mesonychids and Arctocyonids. However, the drier and more open conditions that developed during the second half of the Eocene allowed Hyaenodonts to expand in size and diversity. Some, such as Hyaenodon, would become highly successful predators that ranged from cat to grizzly bear sized, while the Apterodontines developed into semi-aquatic shellfish eaters. Hyaenodonts thrived in Africa due to receiving minimal competition from other groups of carnivorous animals, with some early Miocene forms becoming among the largest predatory land mammals of all time. However, it may have been their relative inflexibility of diet that was their ultimate downfall. Lacking that flat, grinding molars of many carnivorans, Hyaenodonts were more limited to hypercarnivorous niches, with a mouth full of knives being poorly adapted for anything other than slicing meat and crushing bone. When Carnivorans arrived in Africa at the Oligocene-Miocene boundary, the Hyaenodonts may have evolved themselves into a corner in order to avoid competition, making them more vulnerable to environmental changes.
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I feel like Hyaenodonts just had their time. I mean, trying to compete against Bears, Hyena, Canines, & Big Cats in a rapidly changing climate/ecosystem would put extraordinary pressure on any clade of animals; however, the fact that they lasted for almost 55 million years is genuinely mindblowing.
and competing with bear dogs and entelodonts too
It was a clean and beautiful world full of terror.. Amazing animals, pure monsters.. Its amazing how they all died out and then we came.. Somethings wrong there.
Classic case of apex predator dies off and other smaller ones fills the power vacuum
@@MrMarkeZGthese animals were extinct looong before man ever showed up.
Sorry about the quality of my voice in this video. I’ve recently had COVID and am still recovering from it!
I had a hunch! Sad to see it confirmed. Your voice is nonetheless perfectly fine, great vid.
Well done. Thanks
didn't noticed
It isn't very noticeable.
What it's worth, I don't quite hear it. I think your vocal quality is consistent. So it's good in my opinion.
You know it’s a good day when a Dr. Polaris is released.
Now I'm intrigued by these Mesonychids you briefly mentioned.
He has another video on them
@@geoffzuo9831 can u link the video?
Simbakubwa and Megistotherium are one of the coolest names for giant predatory mammals.
I've noticed that many of the jumbo-sized species are "theriums" lol.
@@davidrichard3582 Therium means beast in Latin. So quite fitting.
Clever choice of brand name by the "true" Carnivorans. The Hyaenodonts thought they had them when they unlocked "super-carnivoran". But the Carnivorans chuckled, chewed some tubers, and watched them die out
"Whacha.....whacha sayin?"
I love hyaenodonts since i see it in Walking with Beasts. I can't wait to see the video on the evolution of rhinos, your videos are great! 😍🐻❄️💪
PS I hope in the future you do a video about chalicotheres, other very bizare and peculiar animals 🐎+🦍
It's good to know you are recovering, doc. ❤
Thanks!
I'd really like if we could also get some videos on early cats, dogs and bears
Edit: nonononono simbakubwa's mass was estimated with felid regression systems. Using the same method megistotherium would have had an upper limit of 3 F*CKING TONS. The largest hyaenodonts would have been probably around the 500-600kg range.
Yeah I thought those weight estimates were a bit suspiciously high!
@@dr.polaris6423 ye for an animal not much taller than a kodiak or polar bear a female hippo sounds a bit too big
Always a pleasure too see you upload doc.
Thank you very much for this episode. I have been looking forward to hyaenodonts for a long time! I look forward to rhinos next week.
Yay another dr Polaris episode
OB viously
hope you get well soon dr polaris, thanks for the upload, great work as always!
Doesn’t matter what species or groups you’re covering I always get hyped. Especially with such an iconic group like the hyaenodonts.
Can u do a video on Gorynychus and the therocephalians or anteosaurus and the dinocephalians?
I immediately started hearing the theme from Walking with Beasts when this started
Same here I loved that show my earliest memory was watching walking with the beasts on Netflix on my will 😂 I was 8
Remember, the hyaenodonts were not a homogeneous group of animals, but literally a whole order. As much of an order as the Carnivorans (containing all dogs, cats, and their relatives), or the Proboscideans (all trunked elephant relatives), or the primates (containing all monkeys, apes, and their relatives). A given hyaenodont could be wildly different from another hyaenodont, and separated by millions of years of evolution, in the same way a lion and a wolf are just blatantly not the same thing.
Thank you for your wonderful videos. One small correction: Messel is in Hessia, not in Bavaria
Thanks for pointing that out. I realised that I made that mistake when listening back to the video!
Dr Polaris drops
Drummer daddio stops
You've got my full attention
Your videos are incredible man! Also, I’m still looking forward to your next Speculative Evolution video, I’m excited to see how the dinosaurs keep evolving in your project.
"Babe wake up, a new Dr.Polaris vid just dropped".
The creodonts are fascinating, especially with the evolutionary traits of self sharpening teeth.
Yeah that's a really interesting part of their anatomy. Some species even developed carnassial teeth that rotated as the animal aged in order to keep them sharp!
New research suggests their megistotherium weight could be up to 1300 kg which makes it the largest hyper carnival mammalian
it's amazing how both of the largest Cenozoic land Carnivores lived around the same time.
Simbakubwa in Africa and Barinasuchus in South America.
I mean the largest saurpods all lived around the same time the planets conditions probably allowed for large mammalian herbavores so allowed large carnivores
Simbakubwa isn’t even the biggest hyaenodont (it’s only around 400kg), let alone the biggest Cenozoic land predator.
@@bkjeong4302
Yup.
The largest hyaenodont is still Megistotherium.
And the largest mammalian land carnivore is a tie between Arctodus, and Arctotherium.
@@beastmaster0934 nope
@@bkjeong4302 that’s a blatant lie
Their nickname alone is awesome and I just really like these weird prehistoric mammals
Also this hope you have a good day
You should do a video covering Mesonichidea.
4:00 I'm not 100% certain, but I'm pretty sure that Hyaenodon horribilis was digitigrade, it just had a relatively short metatarsal compared to more specialized cursorial carnivores that would appear later.
Messel is actually situated in Hesse
down in Bavaria you find the famous Lagerstätte of Solnhofen and other similar sites from the Upper Jurassic in the Altmühltal.......and unlike in Messel, which is a protected site, you can go fossil hunting at some places there
Dr. Polaris. Hope are much better. Thanks for your videos. If you ever do a video about the person behind the science I'll be there for sure 🙂
A fantastic group of carnivores!
New drinking game just dropped -- take a shot every time Doc says "civet-like." 😛🤣
Hey all what is the term for being able to rotate "wrists" such as to switch from "running" to "grabbing" or "tripping" prey? Ya know--cats and bears can do it, but canines cannot? I wonder if the hyenadonts were not to some extent disadvantaged vs. later competitors such as bear dogs due to their lack of this feature? Surely that large species of hyenadont you show here looks more like a bear than a wolf. A fearsome creature, but not as versatile as similar predators who had the "cat wrist" feature.
Just a thought.
I think it’s referred to as pronating and I don’t think Hyaenodonts were capable of doing this, much like modern dogs.
Wow some really massive varieties 500-800 KG these are monsters
Hyenodonts Are One Of My Favourite Prehistoric Predators And I Felt Bad When Hyenodon Horridus Got It’s Meals Stolen By Entelodon
That unfortunate fellow in the blue plaid shirt.
Why does "semiaqatic shellfish eater" sound like an insult?
It kind of is.
When I was a child I was convinced that hyenodonts were cetacean ancestors. Of course I confused them whit the family wich Andrewsarchus belongs
Being too specialized always spells danger...
The Hyaenodont in the thumbnail seriously look like Thylacine (Tasmanian Tiger) on steroids. I wonder if the similar appearance is due to convergent evolution? 🤔
Amazing video! Cheers to these wonderful beasts!
yay rhinos (Indian Rhino is my favorite ungulate)
hoping for more permian after that though
Next please the thalatosuchians, the fully aquatic crocodiles from the jurassic
It would be interesting to wonder if any of these were marsupials as many renderings look like extant marsupial predators.
Do you think if we use time machine to send prehistoric animal into modern time
Could hyaenodon survive in modern time expecially in africa?
Could hyaenodon compete with lion,hyena,&leopard?
@The Philosoraptor can hyaenodon take down cape buffalo,hippo or rhino?
@@jasminegobuster3847 I don't know about Hippos. Maybe. It would be a sight to see them attacking fully grown Elephants.
What made Hyaenodonts hypercarnivoroud as opposed to obligate carnivores?
Hypercarnivores get more than 70% of their food from meat.
A mouth full of knives being poorly suited to anything other than slashing meat and crushing bone...
Tell that to the pandas.
Can you please do a video on Barbourofelis?
What would they have behave and sounded like in real life? 🤔
Maybe the closest living equivalent to the Wolf from "An American Werewolf in London" or the Beast of Gevudan.
Still waiting on the next Alter-Earth installment (3)
I'm having a hard time picturing bear-sized hyenadonts attacking rhinos and elephants.
Compared to their current predators, it would seem like a Kaiju match.
In packs maybe?
@@davidrichard3582 Nah. They didn't have the brains to hunt in packs. Hyaenodonts had such small brains that they could not even think of hunting in groups.
@@douglasthescottishtwin3989 They probably hunted smaller Proboscideans, although some predators today can hunt prey much larger than themselves.
I love how exact they are with the weight of that Female Hyena ! 153 pounds or 69.2 kg i mean really could they not say 150 or 70 ? just humorous to me
Scientists are all about being precise, sometimes to riddicolous extents.
Ooh! Now, I do love me some creodonts.
I love the way you keep inventing these crazy animals
I hope you don’t mean that I’m making all of this up!
@@dr.polaris6423 he is probably joking 😅
@@gamerteojuice410 Hopefully. Either that or he's one of those fuckwits that don't believe in evolution and think that scientists make up prehistoric species. Trust me, they exist and they all need to be placed in locked cages.
Survival of the most adaptable
Animals like Simbakubwa make me wonder why the cutoff point for terrestrial mammalian predator size seems to be about a ton. Now that I think about it, fully terrestrial, quadruped predators in general, be they reptile, stem mammal or mammal seem to rarely get over 600 pounds even when there's rhino or elephant sized prey walking around. Kind of makes all the 1 ton+ non-avian theropod stand out even more.
Non-avian dinosaurs have specialized air sacs in their body to counteract with their weight and help their bone support their mass.
I'm a Big Head predator guy, my theory is if you're going to use your Head as a weapon might as well carry around the equivalent of an A-Bomb. for instance I'd have loved to see a Erythrosuchid, the giant headed land croc mimic. Imagine throwing a saddle on that beast and riding it around the Hood. Gators are just big wussies, jump their back and all they can do is thrash around, not much good for riding
Compared to Carnivorans, Creodonts take brawn over brain. They were certainly tough, but much less advanced than canids or ursines.
Aside from Creodonta being possibly polyphyletic, the idea they were outcompeted by smaller but more efficient carnivorans ignores a bunch of things.
- “creodonts” weren’t actually larger overall than carnivorans. This is in large part due to flawed mass estimates that are based on incorrect assumptions about physical proportions. The largest hyaenodont was Megistotherium at 500-600kg (no, Simbakubwa wasn’t 1.5 tons, that was one of those estimates based on inaccurate proportions); that’s a size reached by several carnivorans, even during Megistotherium’s existence (see: big amphicyonids). In fact, on average I’d argue carnivorans are the ones that evolved more “brawn” (size and power) as they produced lion-sized or larger predators far more often.
- most carnivorans are not pack hunters, and most of the extinct ones likely were not. Furthermore, pack hunting does not guarantee dominance in modern predators (tigers are more dominant than wolves where they coexist, for example). So pack hunting probably wasn’t actually an advantage carnivorans had over hyaenodonts.
- most carnivorans aren’t actually specialized for pursuit hunting. In fact, I’d argue that hyaenodonts (which were semidigitigrade or fully digitigrade depending on species) were actually MORE suited to pursuit hunting than most of the carnivorans they coexisted with, seeing as things like amphicyonids were plantigrade (as are many living carnivorans).
- there is little evidence to support carnivorans were smarter than hyaenodonts; for one, relative brain size is a poor indicator of intelligence, and for another, carnivoran brain sizes in the Oligocene and Miocene were lower than in the Quaternary.
- the idea of carnivorans as evolutionary newcomers that overthrew the competition is false and assumed carnivorans came to power much later than when they actually did. Carnivorans first became a dominant group of apex predators around the tail end of the Eocene with the nimravids; this is actually THE SAME TIME as the hyaenodonts also becoming a successful group of large predators (having been relegated to mesopredator niches in the past). In other words, hyaenodonts and carnivorans became dominant AT THE SAME TIME. Furthermore, hyaenodonts were able to successfully compete with carnivorans in both mesopredator and large predator niches even past their time (as recently as the Middle Miocene), seeing as the hyainailourids shared apex predator status with large amphicyonids in Africa and Eurasia during the Miocene and seeing as there were some much smaller (weasel-sized) African hyaenodonts at this point, even well after smaller carnivorans invading Africa.
@@bkjeong4302 All of what you said is very true. But I have one question, could nimravids really be considered apex predators in the Oligocene? It was rare for their species to be larger than 200kg and the herbivores of this time were substantially larger, I have a feeling other groups took this place instead.
@@camacakegd3714
We don’t have that many 200kg hyaenodonts from the Oligocene either (H. gigas is from the very end of the Eocene, the large apex predator Hyaenodon species of the Oligocene were only wolf-sized, and the big hyainailourids of the Miocene hadn’t evolved yet).
@@bkjeong4302 H. Gigas is the only Eurasian species properly studied as far as I can tell, but there are others suggested to be of similar size like H. Weilini in surrounding countries. In fact, there are several species that are poorly studied but are very likely similar in size to H. Gigas throughout Asia during this time.
To be honest, the genus Hyaenodon probably needs some reevaluation. It's a massive wastebasket taxon and reflects the nature of hyaenodont research as a whole; pretty crappy.
A shame you didn't mention that some recent studies suggest hyenadonts might actually be a form of afrothere, due to the way their teeth are formed/replaced
In their 2007 paper on the ptolemaiid Kelba, Cote et al. mention the fact that (at least according to their study) researchers have tended to look outside Africa for the sister taxa of various African groups rather than looking for possible relationships with other African taxa. They mention Afrotheria as the prime example of how the previous idea may not be the case, and also mention that hyaenodontids may have originated in Africa, and they word it in such a way that it might be ambiguously interpreted as hyaenodontids possibly being afrotherians.
It's always such a weird part of biology that successful predators so often reach their biggest sizes relatively shortly before going extinct.
That’s very true. They then become vulnerable to environmental changes as a result of their specialisation.
It should be noted that the idea of smaller, more efficient carnivorans outcompeting bigger, inefficient hyaenodonts isn’t really true…for the simple fact that carnivorans actually stated getting big at around the same time as the hyaenodonts (with the nimravids) and reached their peak at around the same time as the hyaenodonts (the big hyainailourid hyaenodonts lived at around the same time, and often in the same environments, as most of the larger amphicyonids).
@@bkjeong4302 Yeah, for sure it's more like Dr Polaris said, a case of them suffering from over specialization. I just always remember how wrong it felt when I learned that
So Megistotherium was almost double the size of simbakubwa?
Another banger video 😩
Hyaenodonts having long juvenile stage seems odd. You pointed out that the Hyaenodonts have small brains for their body size. Don’t smaller brained mammals tend to have shorter juvenile stages?
Generally speaking yes.
@@davidrichard3582 Perhaps they left their mothers during the end of their milk tooth stage.
Good Video! But Messel pit is not in Baveria but in Messel, Hesse.
Have you seen prehistoric planet and what your opinion and favorite episode?
I what these felidae carnivora like mammals sounded like in life? What do you folks think?
Can you say please the name of the music background? I enjoy it too much not to know it!!!
It’s called Hozen theme and is from the Pandaria expansion of World of Warcraft.
So hyaenalourines or late specialized gigantic forms just like barbourofelids being derived nimravids in parallel forms had two waves of reinvading the Americas with the hyaenodots dying in the Eocene and surviving in Africa in giant forms but the barbourofelids retaking the Americas and lasting until late Miocene
What's up with the stignaclops?
Megistotherium looks like a brute. I wouldn't like to run into that.
It would have probably destpryed whatever it actually fought. Ain't no way even the biggest ever existed apex Lions and other felin stand a chance against it. 😅.
The Messel pit is in the state of Hesse.
DO YOU THINK THEY WERE BASEL MUSTELIDS OR FELIFORMIA
?
Neither, they predated both significantly on a distinct lineage. Those 2 have their own basal taxa.
interesting how bears, tigers, stoats, walruses, raccoons and hyenas are more closely related to each other than to these guys
These where probably first of bone crushing hyena niche predators and then later on got extinct and cats filled its power vacuum and became modern day hyenas
Dangit. Plantigrade? Image at 3:58 does not match the narration.
4:00. Plantigrade feet? Why does all the artwork show digitigrade feet?
A lot of them could have been semidihitigtade, so in between.
I’m sorry, the idea carnivorans outcompeted hyaenodonts really is based on false ideas about the timeline of the fossil record and about carnivorans.
First of all, most carnivorans are not pack hunters, and most of the extinct ones likely were not. Furthermore, pack hunting does not guarantee dominance in modern predators (tigers are more dominant than wolves where they coexist, for example). So pack hunting probably wasn’t actually an advantage carnivorans had over hyaenodonts.
Second, most carnivorans aren’t actually specialized for pursuit hunting. In fact, I’d argue that hyaenodonts (which were semidigitigrade or fully digitigrade depending on species) were actually MORE suited to pursuit hunting than most of the carnivorans they coexisted with, seeing as things like amphicyonids were plantigrade (as are many living carnivorans).
Third, there is little evidence to support carnivorans were smarter than hyaenodonts; for one, relative brain size is a poor indicator of intelligence, and for another, carnivoran brain sizes in the Oligocene and Miocene were lower than in the Quaternary.
Fourth, and most importantly, the idea of carnivorans as evolutionary newcomers that overthrew the competition is false. Carnivorans first became a dominant group of apex predators around the tail end of the Eocene with the nimravids; this is actually THE SAME TIME as the hyaenodonts also becoming a successful group of large predators (having been relegated to mesopredator niches in the past). In other words, hyaenodonts and carnivorans became dominant AT THE SAME TIME. Furthermore, hyaenodonts were able to successfully compete with carnivorans in both mesopredator and large predator niches even past their time (as recently as the Middle Miocene), seeing as the hyainailourids shared apex predator status with large amphicyonids in Africa and Eurasia during the Miocene and seeing as there were some much smaller (weasel-sized) African hyaenodonts at this point, even well after carnivorans invading Africa.
💜💜💜💜💜
Do you think can hyena became top predator in africa if lion and leopard are extinct?
Can hyena evolve to became large and powerful predator like hyaenodon?
Imagine how big they'd get?
It's interesting how many lineages of mammals tried to be predators.
shame they're all gone now.
Uh? Humans? Humans are there too
My ancestors
I heard that their dogs in North America would’ve wiped out hyenodon
you sound so much nicer. beterschap.
God is returning soon I wanted to spread the good news because a lot of people have become hopeless and sad about the state of the world and I wanted to inform you that God is returning soon, I hope you all are excited, I also really love this channel, learning about animals is so interesting and fascinating, all you have to do is accept Jesus Christ as Lord and repent to God of your sins he is a extremely kind and forgiving God and knows everybody makes mistakes :)
I take it the non-avian, sauropod dinosaurs might still be around, otherwise it would seem unnecessary to specify theropods.