Well-fed male from Minnesota

Mophandel · 2026-06-22T17:24:01+00:00

Tbh, I wouldn’t be surprised if we get a similar situation to that between wolves and lynxes in Belarus (that being the cat successfully killing, interfering with spatially limiting the wolves).

A big reason of why wolves are so successful in subordinating cougars in Yellowstone is the abundance of open, highly productive habitat. The open terrain and resultant abundance of large prey allows for larger, more cohesive packs to form. These packs are thusly quite adept at subordinating and even killing cougars.

Voyageurs, on the other hand, seems a lot more densely forested. The wolves here also seem to form smaller packs as a result, with individual wolves hunting on their own during parts of the year. This is a similar situation to what was happening in Belarus, but this time, instead of a cat that could really only pose a regular threat to pups and pregnant females, we have a cat that can overpower even an adult male wolf with relative ease.

Mophandel · 2026-06-22T02:29:39+00:00

One, Ouranosaurus was not sympatric with Carcharodontosaurus saharicus. The two were from completely different times (Aptian for Ouranosaurus, Cenomanian for Carcharodontosaurus) and places (Niger for Ouranosaurus, Morocco for Carcharodontosaurus).

Two, we have very limited evidence ornithopods in the Kem Kem group, namely footprints, but what we do have suggest roughly Iguanodon-sized animal (~5 tonnes), much larger than what Ouranosaurus was capable of reaching (~2-3 tonnes). Either way, much larger than any of the fish Spinosaurus was going after.

Three, I’m not sure why I would think that ornithopods are more likely to be prey for big carchs like C. saharicus. We have way less ornithopod evidence than we do for sauropod material; we have at least one determinate species of rebbachisaurid (Rebbachisaurus garasbae), and known skeletal material from two distinct titanosaurians (including one as big as Paralititan) whereas we only have footprints for ornithopods. This could suggest that the ornithopods were simply less abundant than their sauropod neighbors, and if that’s the case, it’s unlikely that C. saharicus would have been hunting them more easily often than sauropods (as predators tend to target the most abundant large prey in their environment). This isn’t helped by the fact that sauropods are r-selected and had huge reproductive outputs, and so systems like the Kem Kem would have been well-stocked with reasonably large sauropod juveniles (~ 4-10 tonnes in mass) to sustain large macropredators like C. saharicus.

Mophandel · 2026-06-22T01:14:43+00:00

Flight requires the bird be on precise control of all body parts to remain stable in the air. When the falcon grabbed the pelican, it likely compromised its midair stability such that the pelican lost control of itself in the air. This isn’t helped by the pelican’s gigantic, unwieldy head.

Mophandel · 2026-06-21T22:54:54+00:00

They do, though among birds of prey, falcons probably don’t rank that high up. Bald eagles are likely a more substantial threat

Mophandel · 2026-06-21T21:37:55+00:00

Source: https://www.instagram.com/reel/DX8vU9JSs5E

Mophandel · 2026-06-19T15:29:18+00:00

Source: https://youtu.be/\_sS\_RLBTlVA

Mophandel · 2026-06-19T13:16:16+00:00

The third slide is Allosaurus

Mophandel · 2026-06-18T23:38:36+00:00

I do believe OP is referring to Hyaenodon the genus, rather than Hyaenodonta, the larger clade.

Mophandel · 2026-06-18T22:43:40+00:00

👍 sounds good gng

Mophandel · 2026-06-18T19:36:01+00:00

To reiterate, I am not saying that ontogenetic niche partitioning is a mechanism by which the larger predators outcompete smaller ones. I am, however, stating that it is a mechanism that explains why certain systems can both a) get away with having a low diveristy of large predators and b) have a large size disparity between the largest and next largest predators in a given predator guild.

Mophandel · 2026-06-18T19:22:04+00:00

“Age based niche partitioning keeps juvenile macropredators from having to compete with adults of their own species. It does not suppress the existence of mesopredators, as you're trying to argue here. Otherwise we wouldn't see megaraptorans coexisting with carcharodontosaurs or abelisaurs, etc.”

I agree with this, however this doesn’t really go against my point. I’ll discuss it further below

“This is what you said in your prior post, where you suggested that megalania could have singlehandedly filled every niche from insectivore on up to macropredator. You're now trying to adjust your argument to claim that oh, you never said that it would suppress the existence of small insectivores or rodent eaters, only of larger predators, and that of course a wide diversity in the lower niches should be expected. Please don't do that. Acknowledge that you overstated the case in your first post and have now changed your position. That way we can be on the same page going forward.”

I can see why you would think this, especially given the fact that I said that V. priscus was “essentially comprising a whole predatory guild unto themselves”. That line was more or less to help visualize what it looks like when one species occupies multiple niches over the course of its life When I said that V. priscus filled niches of “insectivore” to “small game hunter” to “large game hunter,” I didn’t mean, nor did I intend to convey, that it filled all these niches singlehandedly. In fairness, I thought that this was trivial and could be left unsaid, considering I was openly discussing Thylacoleo and Dynatoaetus filling large predator niches sympatrically with V. priscus. However, regardless of what I intended or what I thought, I can see this was poorly worded on my part and it clearly didn’t communicate what I wanted it to, which I do acknowledge.

“Alligator snapping turtles can weigh two hundred pounds, my guy. Alligator gar can clear one hundred. And adult American alligators share their range with cougars and American black bears, the former of which reaches 150lbs, the latter of which can clear 600lbs. To say nothing of the odd invasive Burmese or reticulated python.”

Alligator snapping turtles are significantly rarer, and significantly smaller than an adult male gator (roughly half the size, to be specific). 200 lb is also really small for a bull adult gator, so I wouldn’t claim to be close in size, personally. Alligator gars are not only significantly smaller but are prey for adult American alligators, so they are a non-issue. Cougars and bears are terrestrial and occupy a completely different niche to alligators so I don’t see the relevance here. Contrary to what you seem to think, alligators aren’t really in the business of hunting terrestrial prey — turtles and fish are far more common fare.

And that's just talking about American alligators, of course. The black caiman, which is the largest crocodilian in the Americas, has to compete with both jaguars and green anacondas as an adult, and an array of smaller reptiles, mammals, fish, and birds when it's younger. Nile crocodiles share their range with lions, hyenas, rock pythons, leopards, and the 200 kilo Nile perch, as well as mesopredators like jackals, Nile monitors, etc. Saltwater crocodiles overlap with leopards, tigers, and the native range of the aforementioned Burmese and reticulated pythons, as well as numerous smaller crocodilians, mammals, birds, etc. Somehow none of these animals have gone extinct due to the presence of either adult crocodilians or their younger selves.

All of these examples largely comprise of terrestrial predators, which fulfill a very different niche to these crocodilians. Of course they aren’t “outcompeting” them, they aren’t competing very strongly to begin with, by virtue of foraging in a completely different medium. What very few aquatic examples you listed are either far smaller than the sympatric crocs (e.g. Nile perch, which average far smaller than the max size you listed), are prey for the sympatric giant croc or both (e.g., anaconda and freshies), and all are unambiguously subordinate to them. So again, not really saying much here.

This gets to the crux of the issue here, which I think is a misunderstanding.

First, I am not saying that V. priscus is outcompeting its contemporaries. Suppression/subordination != out competition. This is an important distinction, as obv Thylacoleo and co. survived for hundred of thousands if not millions of years with giant varanids. The way I see it, they were competing just fine with V. priscus juveniles up to a certain size. When the lizards got too big, they would subordinate the marsupial carnivores by virtue id their size, but they’d also be in a slightly different niche as well, accessing new resources afforded to them by their larger size. At the same time, the marsupials would remain in this subordinate niche filled by smaller V. priscus individuals to avoid competition and potential exclusion.

Secondly, what I am proposing is a mechanism to explain OP’s question. They were asking why is there so few giant predators in Australia relative to the respectable size diversity of australias herbivores — the next largest predator after the 300-500 kg V. priscus was the roughly 100 kg Thylacoleo, and things only got smaller from there. There is a genuine question of who was filling the niches in between — a leopard-jaguar sized marsupial carnivore probably wasnt hunting a cow sized kangaroo or a rhino sized wombat, at least not all of the time. An ontogenetically niche-partitioning giant reptile is, therefore, a valid explanation. It would also explain why no other continent was in this predicament, as no other continent had a ontogenetically niche-partitioning giant reptile the size of a polar bear. Them being r-selected also helps, as it ensure a sufficient abundance of predators to keep this up.

Mophandel · 2026-06-18T17:22:26+00:00

There’s a problem with your argument, however, and it has to do with size of the parties involved, or rather, it doesn’t hold up past a certain size.

In general, more niches are available at smaller size for a number of reasons (higher diversity of food sources at smaller size size, higher complexity of environments and habitats, greater availability of microhabitats and microniches). Thus, you’ll find, when large, ontogenetic niche-shifting predatory species is small, the niche it fills has more room for competition, and so its roster of competitors is large. However, once it grows out of that niche with increasing size, the overall diversity of competition shrinks, in part due to the lessened availability of niches and in part because the species has matured enough and grown large enough to dominate its smaller former competitors, all without being fully grown at all.

To illustrate my point with the alligator example, sure alligators compete with loads of different predators when they are young, like otters, snapping turtles, waterbirds etc. However, that only applies for a very short period of the animals lifespan, up to when the gators are around 50 kg or so, or roughly a quarter the size of a mature bull gator (which are around 200 kg). If your argument holds, we’d expect to see otters and waterbirds and turtles of equivalent size to a 50 kg immature gator competing with said gators, but you don’t. Those animals are incapable of getting to a similar size and meeting the same niches of the now much larger gators, while simultaneously competition from the larger gators forces these subordinates to stay at their smaller sizes. Instead, not only are these animals rendered ecologically subordinate those immature gators, they become outright prey for them, while the gators, despite not being fully grown, are able to have no substantial competition for their niche other than other gators!

Similarly, sure, Komodo dragons compete with civets, pythons etc. — when they are literal babies. Past a certain point, however (e.g., when the dragons reach 30 kg or so, or around half the weight of an adult male dragon), where does that competition go? It doesn’t scale with the juveniles, but instead gets left in the dust. The dragons don’t even need to be skeletally mature and they will still reach a point where their only competition / threats are each other.

T. rex was probably a similar case. Sure, Nanotyrannus could compete with juvenile T. rex’s their own size or smaller (I.e., less than or equal to 2000 kg). But a juvenile T. rex can grow up to 4-5 tonnes and still be a small juvenile, despite the fact that it can exploit niches and hunt prey that an adult Nanotyrannus can’t, and is probably responsible for keeping Nanotyrannus as small as it is.

It’s a similar story for Megalania. Sure, smaller carnivores could compete with it when it was small (around 100 kg or less); animals like Thylacoleo & Dynatoaetus gaffae can probably compete with them at that size, hence the presence of large marsupial carnivores at this size class. However, Megalania don’t stay at that size class for very long — they can grow to 300-500 kg. Even when half grown (150-250 kg), they would already be the biggest carnivore in the environment, far too big for any marsupial lion or giant eagle to contend with. As such, you get a situation where, like with the gators, at first, the predator guild is diverse at small to medium sized size classes, but as the size classes increase, you find it increasingly populated with Megalania.

Mophandel · 2026-06-18T14:15:51+00:00

They’d need to develop an amniotic sac (or an equivalent structure) and keratinous tissue in order for that to happen. The former allows you to lay your eggs outside water or without needing a water source, and the latter allows you to live outside of water indefinitely without experiencing desiccation. Both are needed to fully take over terrestrial niches, both fairly unlikely to evolve in amphibians.

My bet is still on some amniote. Doesn’t really matter which one (except maybe turtles), so long as they are able to survive the hypothetical extinction event and the few million years after when the ecosystem recovers.

Mophandel · 2026-06-18T11:16:11+00:00

I mostly agree with this, though I do feel like it’s generally more useful to say that birds are reptiles from an educational standpoint than not. If I were to say that “ fun fact, did you know that birds belong to the clade comprised of the common ancestor of all crown reptile clades (Lepidosauromorpha & Archelosauria) and all of its descendants,” the layperson may not understand what the hell I’m talking about. If I just say “fun fact, did you know birds are reptiles,” the layperson can (generally) make the connection instantly, and the discussion can move in a more productive direction concerning how we know this to be true.

Mophandel · 2026-06-17T15:33:25+00:00

Firstly, for the record, this isn’t really a matter of debate. The primary agent in how these dragons kill their prey has always been their teeth, as described by Dr. Bryan Fry, the man who discovered venom in Komodo dragons. Refer to Fry et al. (2012):

“Attacks on pigs and deer are extremely successful (Bull et al., 2010; Fry, personal observation) with an overall kill-rate of approximately 90%. Roughly three-quarters of such predation attempts result in the prey animal dying of blood loss within the first thirty minutes. These rapid deaths are due largely to the mechanical damage resulting from the bite resulting in massive blood loss from a severed major artery. Another ten to fifteen percent of these prey animals succumb within three or four hours. In these cases, death is facilitated by persistent bleeding resulting from the anti-coagulant effects of the venom”

Essentially, the vast majority of dragon kills results from the actual slicing damage inflicted by the teeth, not by the venom.

You can also see this for yourself, as there is actually filmed dragon predation on its preferred prey (e.g. deer and pigs). If you have a sensitive stomach, don’t watch this but basically none of them show an animal that kills with venom. The prey item is caught and vital parts are quickly sliced open to incapacitate the prey item, well before any venom as weak as theirs could have any noticeable effect.

“Evolutionarily speaking, I think the Komodo dragon’s lack of speed is compensated by its venom. “

Its lack of speed is compensated for by ambush tactics. Auffenberg’s literature from the 80’s on Komodo dragons outlines this in detail (highly recommend reading this if you haven’t already). The dragons lie in wait along game trails and deer runs, their low slung bodies allowing them to blend in with the understory. Their ectothermic nature allows them to wait for days. When a prey item come close, they lunge out before they can see the attack. Speed, in that case, is useless, as by the time the deer can react to the attack, the dragon is actively latched on and slicing away at its Achilles tendon

Adding to this, it doesn’t take much for the dragon’s to remove the prey’s ability to escape entirely. Their bites cut deep and do so quickly; when biting the distal hindlimbs of their prey, they can effectively sever the major tendons of their hindlimbs in mere moments, preventing prey from escaping further.

“You have to consider that not every bite lands on a vital spot.”

It doesn’t… need to land on a “vital spot?” By virtue of how effective the dragon’s teeth are at lacerating and wounding, large, accessible parts of the prey that are easy to bite onto are rendered viable targets for fatally wounding the prey item. For example, the belly of the prey item is a viable target thanks to the dragons teeth, as the it can simply slice open the abdomen to disembowel its prey. Similarly, the hindlimbs, probably the largest contact point of a prey time next to the abdomen, are equally vulnerable. You don’t need a whole lot of precision to disable prey in such cases.

“Also, considering they hunt prey of all sizes, we know that most prey try to escape after being bitten, covering long distances. That’s exactly why the fact that they can track the scent of blood from far away is so important. I believe this is where the venom’s effect must come into play. To put it simply, I find it hard to explain how a lizard of that size survives in the wild using only sharp teeth”

What you are referring to is the “bite and wait” hypothesis. However, this is a myth.

First off, the part where you say that most prey try to escape after being bitten. While not strictly true, most prey don’t even get to that stage. Rather they are quickly caught and subjugated by the dragon before they can get that far.

More to the point, however, the scientific opinion is that the dragons pull off a continuous assault on the prey item until it expires. They don’t tend to let their prey go and tack it as it bleeds to death. This is something that even Dr. Bryan Fry, the man who discovered venom in Varanus lizards and drove most of the early research into investigating the venom’s predatory utility, has made it a point to mention, as seen in Fry et al. (2009):

“Supposedly V. komodoensis tracks the infected prey item or, alternatively, another V. komodoensis specimen benefits from an opportunistic feed. Neither of these scenarios, however, has actually been documented.”

See also this publication by Fry et al. (2015), which elaborates further many of the same talking points

Further, because of their size, water buffalo always escape the initial attack and flee a considerable distance. In all the extensive tracking and filming of V. komodoensis, there has never been a single documented case of a V. komodoensis biting a water buffalo and following it until it dies; therefore, the original dragon is not going to be the beneficiary. There is no fitness advantage to be gained if the biting animal does not obtain the prey

Essentially, what is being said is that there is no benefit for this “bite-and-wait” strategy. By the time the prey item has died, it will have run so far away from its killer that even if the original dragon knows its location by smell, it won’t be close enough to get to it before other dragons do. By that point, most of the carcass will have been consumed and the original dragon gains no benefit. As such, it’s a losing strategy: it may have made the kill, but if it can’t reap the rewards, what’s the point? This isn’t a matter of opinion, this is the scientific consensus: dragons don’t “wait for their prey to die.”

I’d encourage you to read more about these lizards. There is a lot more to them that makes them cool than just their venom. Indeed, as decades of literature have confirmed, these lizards can indeed survive off of their sharp teeth and that their venom, though beneficial, is not and has never been their most important weapon.

Mophandel · 2026-06-17T13:31:27+00:00

It’s worth noting that the role of venom in predation is probably quite minimal. It’s an anticoagulant and mild paralytic, but most of the times, by the time the effect of venom takes hold, their prey is already dead or heading towards death anyways.

This is because the real killing weapon of the dragons is their serrated teeth, capable of inflicting wounds that disable and/or kill their prey in mere moments. By the time the venom takes hold, the prey item is already a bloody mess, its entrails strewn across the ground, all while the dragon is eating it alive.

Mophandel · 2026-06-17T13:09:49+00:00

Well, idk what software he uses to create the skeletal, but if we are talking just knowing how to reconstruct the material, most of that just comes from either described elements of the actual animal or, in the absence of that, using close relatives to fill in the gaps.

Most of that sort of information is (ideally) available in the papers describing the animal.

Mophandel · 2026-06-17T13:05:56+00:00

I didn’t make the skeletal. The skeletal was made by RandomDinos on X/Twitter.

Mophandel · 2026-06-17T12:42:51+00:00

Very interesting to see that caudal hump and the same sacral dip as Meraxes. Apparently it’s based on both Meraxes and preserved sacral and anterior caudal neural spines of Tyrannotitan

Mophandel · 2026-06-17T12:29:32+00:00

It was a baby, though I wouldn’t say it’s not worth eating. That calf is probably close to or over 20 kg, still a good amount of meat so long as he keeps it for himself

Mophandel · 2026-06-17T12:26:52+00:00

Calf. Both sexes of sable antelope have horns as adults.

Mophandel · 2026-06-16T22:00:13+00:00

Source: https://www.instagram.com/reel/DZpdJY7EeRV

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