The Bear Necessities: The Rise of the Tremarctines 

I laughed at this harder than I probably should’ve.

I hate that this pun made me laugh.

The South American foxes (aka the Cerdocyonina tribe) are a transient group between the true foxes and true wolves. And phylogenetically between these two groups. Wolves evolves from foxes-like animals ancestors, and the South American foxes. And the species of South American foxes all have both foxes and wolves traits in the same time. Because of this, they can be also called "Wolf-foxes" or 'Foxes-wolves" canids. The Fuegian Dog wasn't a dog but a domestic South American foxe, more domesticated than the current domestic Silver Fox from the Red Fox (this latter having mainly his behavior edited, nothing more). Should be good to have a hint on all that in the next video. I agree on that.

@@indyreno2933 Wait a second ! You're the guy that give false taxonomic phylogenetic trees ! You already made one somewhere in the comments list of the current video, but with the bears ! Why did you do that ! What did you do the same thing with the canid !

Biotic interchange is a helluva drug

Jaguars also got smaller

& no true wolves in South America

Like said in this video, it's because these bears were among the very first carnivoran to go in South America where there wasn't any real big predators anymore to compet with (Terror Birds, Sparrassodonts and giant Sebecid land crocodiles all become enterely extinct way before for some or at the time of the interchange for the others). Due to this, they start a short dominion of their own which allow them to increased their size. Plus, their spead was help and quicker due to the fact that these bears were more cursorials and endurant walkers capable to travel long distances per days, thank to their slightly longer legs compared to the others kind of bears. It's only when canid and big cats arrived that forced again the bears to become again smaller to avoid competion.

The fact that the North American species of Short-Faced Bear, especially the Giant ones, like Arctodus, lived in low density population that created a low genetic diversity pool, was likely due to the fact that they were less sedentary and more nomadic than the others species and kind of bears. In addition to have bigger territories. These elements are clearly obvious due to the anatomy of these animals. These bears were more cursorials and endurants walkers capable to travel long distances per days, thank to their slightly longer legs compared to the others kind of bears and their lighter weight. Such traits and lifestyle help them too to spread more quicker everywhere, or to conquer areas and into new territories more faster. Which is why they spread first among the first carnivoran to go into South America before all the others species of Canid and Big Cats. So, it's kind of ironic that their most distinctives traits that allow them to their success were the same that made them vulnerable as the same time. Unrelated, but even if these bears were mostly omnivorous with a preference tendancy for herbivorous and were highly flexible in their diet, it's however pretty safe to said that was an actuality that the giants species such Arctodus and Arctotherium were able to actively hunt big/macro preys, mostly young specimens, of large herbivores such Bison, Elephants and horses, like we oftently depict them in paleomedias. Because these bears were enough big, strong and fast to chase and slay living animals. Every bears are omnivores, with a diet mainly herbivorous and a small part being carnivorous, and even here eating most of the time flesh from carrions than from animals they themselves killed. But most bears do active hunts time to time following the situations. This was obviousely also the case of the Giant Short-Faced Bears, just a little more than the extants bears.

Giant, not Great.

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At the same time, it’s equally if not more ridiculous that a very widespread and generalized omnivore like A. simus could be killed off by the same sorts of climatic changes that it had survived earlier in the Pleistocene.

species, not specie, species is singular AND plural

@@Dr.IanPlect as the same time ? ok, will correct that.

@@dudotolivier6363 Yes, species applies to ONE, AND more than 1.👍

@@Dr.IanPlect Outside this grammatical error, we are all agree that what I pointed out is pretty accurate and absolute truth. Yeah.

@@dudotolivier6363 Yeah, good info.

Very unlikely, just because Spectacled Bears live in the Andes Mountains (a very rainforest-like environment) The various Ursus species all have different fur based on their environment and since the giant short-faced bears lived in a grassland environment, it’s likely their coloration was more like a Grizzly Bear than a Spectacled Bear

Agree with MarioMouse. Only the species of tremactines living in South America and in forested biomes was likely to have a similar fur to the current Andean Bear.

@@mariomouse8265 But that is making the assumption that the spectacled look appeared because of the the ecosystem (an apomorphy) rather than being pleisomorphic i.e. ancestral to the group. That's mostly what I meant in strictly scientific terms, but I see your point.

@@bustavonnutz Well I’m not aware of any scientific literature where the other Short-Faced Bears share the black and white coloration of their modern cousin; much less that this trait is ancestral to the family as a whole I’m making a guess just based on a pattern I see with the Ursidae species - Sun Bears, Spectacled Bears, Moon Bears, American Black Bears all have black fur despite belonging to the same genus; and all of these animals inhabit dense tropical or subtropical forests while American Black Bears can often exhibit brown or even white fur (temperate climate?)

@@mariomouse8265 It's basically just a question of what can be considered ancestral vs derived among this specific lineage of Ursids; ultimately just a thought experiment since it's impossible to figure this out from fossils alone. Still, the habitat & local climate does play a role on selection, yet exaptations or sexual selection can often result in the bucking of trends. I guess it's fair enough to assume, as many Paleontologists have done, that the Florida Spectacled Bear had the facial mask by asserting that it's characteristic of Tremarctos; however, there is zero current data to support such an assertion for Arctodus unless we found an intact genome that we could sequence & compare with modern Spectacled Bears. Still, I think that there is a valid point to be made on the claim that you'd see more diversity given how different Ursids can be, I mean Polar & Brown Bears aren't even considered seperate species under a biological species complex & they are as different as night & day. If that trend also applied with Short-Faced Bears then there is solid precedent to stand on there as well.

What does any of that have to do with the video?

I saw that thumbnail image and I couldn't resist the joke!

@@dr.polaris6423 i think this bear was the only predetor that beat barinasuchus by weight

Why ask about a canid on an ursid video?

MacFarlane's Bear

@@Dr.IanPlect 'My bad! I was reading a tweet!' - Ted.

@@alaricbragg7843 👍

I’ve heard about that. Even though spectacled bears are strongly herbivorous, they will sometimes attack large ungulates.

@@dr.polaris6423 Well look like it was eating the poor cow

@@dr.polaris6423 In addition, that was a rare case highly provoked because these specific specimens only actively hunt due to the fact they were hungry and haven't any others food sources due to living in a human density area with big farms, that have reduce their forest and as an effect, their normal food sources.

"It's" is a contraction of "it is"; "its" is possessive.

well not for long... Homo Floridanus would use it as sex slave, guard animal and meth mule..

Unlikely due to human conflict.

"It seems ursines just never developed carnassials" - that's a lazy, throw away comment, and clearly inaccurate along the way

@@Dr.IanPlect if inaccurate, then which bear has shearing molars?

@@sciencegeekgrandpa8 This is regarding "It seems ursines just never developed carnassials". I have an example that simply shows this is not so; Polar bears have developed carnassials distinct from its brown bear ancestor, in the direction of a more carnivorous diet. Specifically a more jagged and sharper carnassial profile. That's all is necessary to deem your comment inaccurate. As I stated, that's a lazy, throw away comment, and clearly inaccurate along the way. You may have meant the even more distinctive presentation of a hyena, canid or feline, but your wording wasn't specific enough.

​@@Dr.IanPlect Regrets if my remarks seemed less than respectful, but can we return to my actual question: what is the evidence concerning the diet of Arctodus simus?

Arctodus Simus was not largely herbivorous everywhere; instead its diet depended on its environment. In the southern parts of North America where it was warmer and there were more plants, it ate plants. In the cold north where there were more animals, it ate meat. It was an adaptable omnivore like modern bears, and just like them, was fully capable of hunting when it needed to. Also, bears do have carnassial teeth, they're just not very developed like in other carnivorans

By mysterious coincidence, so am I!

The cave lion is Panthera spelaea, and nobody should be following Indy Reno's made up taxonomic schemes that aren't actually supported by published evidence.

You never provide any supporting evidence for your made-up taxonomic schemes that are not supported by any actual scientific evidence. Spamming your fantasies do not make them real. You're not an expert. You're a crank.

@@ivankwan9264 FOR THOSE UNAWARE, this commenter (Indy Reno); Dogmatically ignores criticism and continually posts flawed taxonomies. It's always the same; he posts flawed taxonomy, I correct it, he ignores it and posts even more bs. I'm a PhD zoologist and detest this kind of misinformation and ignorance. Ivan From your own reply, it seems you are aware of this pest. I've been noting his utter drivel for 8 years now. The correct taxon; Panthera spelaea As for his second message of drivel; - NO, Panthera has far more than 4 species (including extinct, as he does), the ignoramus ridiculously states the tiger is in Uncia, the worst I've ever read from Reno! - lio, tigris, spelaea, atrox, onca, pardus, uncia are all concretely Panthera, not the unsupported assertions he claims above - no doubt if I go through that long comment there will be many more examples of nosense too ------------------ Reno; your stubborn adherence to dumping taxonomic drivel serves no one, it's just misleading misinformation and a perversion of my profession. You are a disgrace.

@@indyreno2933 FOR THOSE UNAWARE, this commenter (Indy Reno); Dogmatically ignores criticism and continually posts flawed taxonomies. It's always the same; he posts flawed taxonomy, I correct it, he ignores it and posts even more bs. I'm a PhD zoologist and detest this kind of misinformation and ignorance. Ivan From your own reply, it seems you are aware of this pest. I've been noting his utter drivel for 8 years now. The correct taxon; Panthera spelaea As for his second message of drivel; - NO, Panthera has far more than 4 species (including extinct, as he does), the ignoramus ridiculously states the tiger is in Uncia, the worst I've ever read from Reno! - lio, tigris, spelaea, atrox, onca, pardus, uncia are all concretely Panthera, not the unsupported assertions he claims above - no doubt if I go through that long comment there will be many more examples of nosense too ------------------ Reno; your stubborn adherence to dumping taxonomic drivel serves no one, it's just misleading misinformation and a perversion of my profession. You are a disgrace.

@@indyreno2933 Reno, for once, why don't you have a discussion with me about all this taxonomic misinformation you post? Tell me why, what motivates you etc...

There is no way to pet an ancient Animal :( unless we resurrect it somehow

@@Patrick3183 Says you, pathetic mortal constrained by the linear flow of time.

If possible, be more careful with them than Black & Brown Bears.

'''''''''''

(A)rctodus simus (A)rctotherium angustidens

(A)rctodus simus

The most carnivorous bear, the polar bear still eats berries on occasion. A lot of animals within the suborder caniformia will readily eat fruit and starchy vegetables. Even species such as the Dhole, a canid with hyper-carnivorous adaptations supplements it’s diet with fruit. I think Arctodus due to having more carnivorous dentition would have feed on fruit in a supplementary manner only. Would scavenging provide Arctodus with enough food calories ? Other large predators such as dire wolves, American lions and smilodons would have probably readily scavenged carcasses.

@@Reyma777 yes of course If a short face bear killed a pre-animal like a horse and it was filled up other scavengers would eat it too but I do think that it is a scavenger than a hunter but they can still hunt don’t get me wrong

Dude, all the kids are using this crazy new thing called punctuation.

@@slappy8941 what?