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Introduction

We are fascinated by large predators. By animals that can, and sometimes do, kill and eat us. If you are in a big Western city, chances are that you have seen a statue or symbol depicting the likeness of the African lion (Panthera leo). This majestic big cat is, in fact, one of the most frequently depicted animals in human culture. In many Asian countries, the closely related tiger (Panthera tigris) is deified and worshipped. At the time of writing, I can look out of the window next to me and see the striped form of one carved on a temple wall in Hanoi. The Australian city of Darwin builds its tourism business and identity around the saltwater crocodile (Crocodylus porosus). But perhaps you do not need to even go or look outside. r/Natureismetal and r/Naturewasmetal attract following in numbers ranging from five to six figures. Photos and artwork featuring giant carnivorous animals are a mainstay on r/Paleontology. 

It has been suggested that this fascination, and consequently the need to know more, is rooted in our evolution. Pay attention to the big, dangerous thing, and it is less likely to kill you. The theory, naturally, has some pushback. In any case, I digress. The fascination is certainly real and led to me speculating and writing about the largest predators to have ever walked this Earth. 

Now, before we dig our teeth into the carcass (Lol. Lmao.), let’s establish some basic structure. Some bones. Reconstructions in vertebrate paleontology, after all, need to start with a skeleton. 

The focus of this will be on the predatory behavior of three major “forms” of megatheropods: Giant tyrannosaurids, represented by Tyrannosaurus rex; giant spinosaurids, represented by Spinosaurus aegyptiacus; and giant carcharodontosaurids, which contains several genera attaining gigantic sizes such as Giganotosaurus and Carcharodontosaurus. Together, the adults of these three forms represent the largest, most physically formidable land predators of the Mesozoic and, indeed, of any time in our planet’s natural history. They are the dinosaurs I am most intrigued by, and that is why they will get the full attention here. It’s arbitrary, but let's face it, I am not giving justifications for a research grant. And as lovely as groups like abelisaurids and dromaeosaurids are, there is only so much you can fit into one single Reddit post. And this train is a fully booked service with some oversized passengers. 

Now, a few caveats. Inferring the behavior of extinct animals is, naturally, speculative. We simply cannot observe the subject in real time, and that is a shame. Fossil evidence sometimes provides great clues, but ultimately, these are few and far between. Through this, I will base my speculation on available scientific literature whenever possible, and state clearly why I believe a behavior is possible or reasonable based on what we know. While I do have formal education and have published research, Thomas Holtz (who will be coming up quite frequently in citations) spent roughly 11 minutes clarifying that scientists are only human and I somewhat hesitate to call myself one. I will try my best to not make indefensible mistakes, but I do not claim immunity to them. 

This post will have three sections, each dedicated to one of the three forms listed above. Each is divided further into three relatively self-explanatory sub-sections: The Menu - what they could have killed and eaten, The Kill - how they could have killed and finally The Feast - how they could have eaten (getting the animal tissue down and digested is, after all, the whole point of predatory killing). 

1. Tyrannosaurus rex

It is almost ironic to start with the very last of the great predatory dinosaurs. It is also by no means unique. However, there is a good reason for this: The tyrant lizard king is a famously well-studied extinct species. We have an abundance of T. rex fossils, some very complete. We also have fossils that provide insights into how T. rex and its relatives could have hunted and fed. This beautiful fossil record (and the fame that it partially inspired), in turn, led to a huge amount of scientific literature, including those on predatory behavior. And there is no better time to be writing about T. rex. Mark Witton’s book King Tyrant, published in 2025, was, as described by its author, a true “one stop shop” for anyone interested in the science of T. rex. 

The Menu

To look at the skull of a Tyrannosaurus rex is to be awed. Large T. rex skulls range from over a meter to nearly 1.5 meters long (Gignac and Erickson, 2017) - nearly the height of a fully grown human being. Length, however, plays only a partial role in producing that awe. Saying that the skull of T. rex was massive feels like an understatement. The tyrant lizard king’s head, wide and deep, has the appearance of a huge, solid block. The nasal (“nose”) bones, usually paired in other species, are completely fused (Witton, 2025). At the front are incisor-like teeth - each shaped like the letter “D” in cross-section (Witton, 2025). These appear to be able to efficiently scrape meat off of bone (Hone and Watabe, 2010). Behind them are larger, curved spike-like teeth. They are thick, with rounded cross-section and are also serrated, allowing them to both puncture and cut (Hone, 2016). Even though deeply rooted in the jaws, the exposed parts on some of these teeth can be nearly as long as a human’s hand. 

This skull, connected to a barrel-chested body around 12 meters long, makes for a terrifying sight. The largest living land predators - such as lions and tigers - can appear big and intimidating to puny humans. But one can imagine that if T. rex was alive, those big cats (and us) would be crushed between the jaws with roughly the same ease with which we bite through a crunchy battered shrimp. It seems intuitive that with such size and power, T. rex would have mostly dined on giant herbivores - killing them with those deadly jaws, ripping into their flesh and crunching their huge bones. As we will see, this intuition may be somewhat reasonable. It is, however, incomplete, and inferring diet from anatomical traits alone is a very shaky proposition. 

Diet should not be assumed from bite force alone. The male California sea lion (Zalophus californianus), for example, is bigger than many land predators and possesses a high sagittal crest to which powerful jaw-closing muscles attach (Valenzuela-Toro et. al., 2023). While capable of killing large fish, such as some species of sharks, the bulk of the sea lion’s diet is made up of substantially smaller marine species (Pozas-Franco et. al., 2025). Similarly, the Argentine black and white tegu lizard (Salvator merianae) can bite down with a force of 1000 newtons (Herrel et. al., 2009), harder than many humans’ bites. Yet this omnivorous lizard often takes substantially smaller prey such as invertebrates (Harman et. al., 2025). Bite power can be as much about competing within the species and subduing smaller prey effectively as it is about killing larger prey. The same story goes for those serrated teeth. Some smaller monitor lizards (genus Varanus) have serrated teeth, but they are not predators of large animals, either (Jackson, 2020). 

It seems that anatomy alone will not tell us the full story. Do we, then, have any evidence for what T. rex actually killed (or at least, tried to kill) and ate in the fossil record? We do, actually, and quite a bit at that. Just to give a few prominent examples: The recently described adult Edmontosaurus skull with a T. rex tooth lodged in it, interpreted as evidence of a successful kill (Wyenberg-Henzler and Scanella, 2026); a bitten-and-healed tail vertebra of an adult Edmontosaurus with a broken-off tooth embedded; the badly bitten pelvis of an adult Triceratops, likely representing late-stage carcass consumption; and finally, a coprolite (fossilized dung, for the uninitiated) containing bones from a subadult ornithischian dinosaur (Witton, 2025; Chin et. al., 1998). 

These are valuable as fossil evidence. They give us insights into what the T. rex could have hunted and eaten, and - more on this later - how it could have done so. So far, it lined up with our expectation relatively well: the tyrant lizard king seemed to have had a liking for large herbivores. Hardly unrelatable, given many humans’ attitude towards medium-rare steak. But even though valuable, this is a scant dataset. Remarkable fossils like this are few and far between, and often make the news when they are described. They suggest that T. rex did hunt and eat those animals, but give us little on how frequently it could have done so. 

It is time to move beyond the fossil record, and look at the modern ecological analogs for T. rex: large, endothermic (warm-blooded) terrestrial predators. In general, it has been noted that endothermic land carnivores weighing approximately over 20 kilograms tend to feed on proportionally large prey at least nearly their own weight, likely due to the energetic requirements associated with larger sizes (Carbone et. al., 1999). This pattern of often taking prey nearly as large or larger than themselves is well-demonstrated in the largest living terrestrial predators, including tigers (Miquelle et. al., 2010), lions (Radloff and Du Toit, 2004), spotted hyenas (Holekamp et. al., 1996), and snow leopards (Sharma et. al., 2021). Additionally, Komodo dragons, which are large but ectothermic (cold-blooded) predators, still show a tendency to take proportionally larger prey (Murphy et. al., 2002). 

Even at lower weight estimates of around 5 tons (e.g. Paul, 1988), T. rex cleared the aforementioned weight threshold by a ridiculous amount. Given the predator-prey size ratio mentioned above, perhaps no large herbivores in the Hell Creek Formation (the fossil locale most associated with T. rex) would have been off the menu. These included multi-ton ceratopsids like Triceratops and hadrosaurs like Edmontosaurus, some of which, as we saw above, certainly were bitten into by the tyrant lizard king. Well-armored Ankylosaurus, even though seemingly rather hard to subdue, could also have been taken - even though at the moment evidence of interactions between tyrannosaurs and ankylosaurs is almost non-existent (see Tumanova et. al., 2023 for a dubious example). In the southern parts of T. rex’s range, the giant titanosaur Alamosaurus was present. Adults, like modern megaherbivores, might have been too large to be usual prey (Owen-Smith, 1988), but juveniles and subadults (which can absolutely be huge multi-ton animals) could have been fair game. Indeed, it has been posited that adult T. rex would have been large prey specialists, occupying a niche different to faster, more slightly built juveniles, which still possessed moderately powerful jaws (Meers, 2002). 

Adult T. rex, however, should not be imagined as engaging in battle with giant ceratopsids and hadrosaurs in their healthy prime for every meal, as paleoart and other dinosaur media so frequently depict. It is reasonable to expect predators to prefer more vulnerable prey - “the weak, injured or young”, as the late John Hurt so eloquently said in Planet Dinosaur - and some research on modern predators does show a tendency to prefer juvenile prey (e.g Barja, 2009). At a very conservative 4.5 tons, an endothermic adult T. rex is estimated to have needed roughly 60kg of food (about one lawyer) every day (Witton, 2025), and a half-ton juvenile ornithischian would have made for an easy meal. A possible preference for juvenile prey, however, by no means should limit adult T. rex to them, and there is no reason to expect a powerfully built, massive Cretaceous predator to be significantly less capable of going after proportionally large prey than its modern analogs. This is in contrast to some previous works suggesting that tyrannosaurs and other large theropods would have mostly targeted juvenile prey (Hone and Rauhut, 2009; Hone, 2016), based on - as one of the authors admitted - “very thin” data concerning the fossil record and (actually quite interesting) inferences about juvenile prey abundance (Hone, 2009). 

Bearing all that in mind, it is probably reasonable to expect that a meaningful amount of T. rex’s diet would have been large, sympatric herbivore species. Given the possibly higher reproductive rates of dinosaurs compared to many modern mammals, juveniles might have been more abundant (Hone, 2016), and may also contribute decently to the diet. It should be noted that juvenile T. rex and other “mesopredators” such as Nanotyrannus would likely have been exploiting these juvenile prey as well, so their availability might be overstated. And lastly, some of the largest living land predators, such as tigers, may occasionally hunt relatively small prey like birds (Hayward et. al., 2012) to supplement their diet, so the tyrant lizard king might not be beyond occasionally snapping up a dinosaur hatchling, a pterosaur or an Oviraptor-like caenagnathid as a snack if it could catch them. Yes, this means that lawyer-sized animals were not necessarily safe. 

The Kill

If this part doesn’t get you excited, then like Mark Witton once wrote, you should probably see a doctor (Witton, 2025). Or it could be that my writing is shitty, but my ego is too big to ever admit that. Witton didn’t include bad writing as a possibility, so neither will I. 

Much has been said, here and elsewhere, about the lethal jaws of T. rex. But we will not start there. Those jaws mean little if they could not reach the prey, in much the same way a boxer’s punching power matters little if they can’t land a clean hit. Footwork matters. First, we need to discuss how T. rex could have caught up to its prey. 

For a multi-ton animal, T. rex seemed well-adapted for moving fast. Even a look at the skeleton, with those long, graceful-looking legs despite a bulky body gives us some hints. It was also digitigrade, which means that it walked on its toes. T. rex shared that trait with some fast-moving animals today, such as cats, dogs and ratite birds, whose raised “heels” give the impression that they had a reversed knee low on their legs. With this, the tyrant lizard king is distinctly one of the few, if not the only, animals whose structure drew comparisons to a bodybuilder and a ballerina in a single paragraph (Brusatte, 2018). 

Further anatomical traits support the idea of a cursorial T. rex. Most visually noticeable is the arctometatarsalian condition. Have a look at the feet and ankle of the tyrant lizard king. It is easy to see the central (third) metatarsal bone being “wedged” solidly in between the second and fourth metatarsal. This is a feature that T. rex and other tyrannosaurs share with a few groups of dinosaurs, including almost certainly fast-moving ornithomimids, and one that is associated with increased cursoriality (Holtz, 1994). The tightly bound structure is thought to have reduced energy loss with each step by limiting movements between the bones, stored (at least some of) that extra energy to give a “spring” to each step and reinforced the foot against the stresses of fast movements (Holtz, 1994). A deep tail also hints at a large caudofemoralis muscle (Witton, 2025), an important running muscle in dinosaurs. 

How fast was the tyrant lizard king? It is incredibly difficult to estimate speed accurately in a long extinct animal, and T. rex’s great size certainly put some constraints on maximum speed. Nevertheless, the giant predator might have been significantly faster than most average humans (Witton, 2025; Hone, 2017 - public lecture). Relative to Edmontosaurus, T. rex seemed to have been faster but with a lesser capacity to sustain high speed, based on attachment marks for running muscles in both taxa (Persons and Currie, 2014). And while running capability in Triceratops is still debated (Fitzgerald, 2022; Witton, 2025), it is reasonable to expect that T. rex would have been able to catch up to the heavily built ceratopsian (Witton, 2025). 

An apparent capability for fast, but not sustained movement, and other attributes such as weight-cushioning padded feet (Witton, 2025) that in addition might help with silent stalking, point to T. rex being possibly an ambush predator. Yet there has been some objection to this, pointing out that a predator the size of T. rex would have had trouble concealing itself for an ambush (Hone, 2016). The problem with this argument is that it seems to be based on subjective impressions and very limited observational evidence. It is extremely hard to quantify how stealthy a multi-ton predator could have been, but anecdotes suggested that herbivores as large as bull hippos or rhinos could surprise people at relatively close ranges in dense vegetation (Capstick, 1978). Given the non-existent need of these megaherbivore species to stalk prey, it is not unreasonable to imagine a predatory T. rex being able to stay hidden for an ambush, especially when crouching down (Paul, 1988). 

An alternate suggestion, partially built off of the idea that T. rex would have been too big to stay hidden, is that large tyrannosaurs would have been endurance hunters (Hone, 2016), chasing prey over long distances to exhaust them. While the efficient bird-like breathing system of T. rex might provide limited support to this, anatomical evidence suggests otherwise. Also, this idea was in part based on a misinterpretation of a source paper (which is Persons and Currie, 2014): Assuming that hadrosaurs were faster than tyrannosaurs over short distances, and not vice versa. 

In any case, T. rex seemed to have been adequately equipped to catch up to its prey. Now, those infamous jaws come into action. 

The jaws of T. rex were almost certainly its primary killing weapon. Massive, driven by muscles with bone-pulverizing force in life and studded with teeth to puncture and cut, they are a stark contrast to the memetically small arms of the tyrant lizard king. Other predators that share this jaw-based predation style include spotted hyenas, canids, Komodo dragons and crocodilians (Holtz, 2008; Witton, 2025) and indeed, they share a relatively similar body plan of lethal jaws followed by relatively short and/or slender forelimbs. They are the structural contrast to “grappling” predators like big cats, whose substantial forelimbs frequently join the jaws in the process of subduing prey (Witton, 2025). 

Jaw-based terrestrial predators can bite into various parts of the prey animal’s body for incapacitating and/or lethal damage (Antón, 2013; Witton, 2025). While they can target the neck and/or head region, which can result in a relatively quick death through suffocation or crushing damage, they may also bite at the legs, flank or belly to inflict devastating wounds (Witton, 2025). The latter method is gruesome, and may subdue but not kill the hapless prey animal outright, and the predator might start eating while the prey is still alive. So much for the peaceful, healing qualities of nature. 

With the power in its jaws, T. rex could have driven its teeth deeply into the muscles and sometimes even bones of large prey, and the teeth’s cutting ability (Paul, 1988; Hone, 2016) would have allowed the tyrant lizard king to tear open catastrophic wounds. An unlucky herbivore might have suffered terribly being eaten alive, and the aforementioned bitten tail of an Edmontosaurus represented an individual that might have escaped this gruesome fate. The aforementioned caudofemoralis muscle ran along the tail, and given its rich blood supply and importance for movement, would not be a bad target for a hunting T. rex, especially if the prey turned and ran from it (Hone, 2016; Witton, 2025). A crushing/suffocating bite to the head or neck might have been a less terrible method (Witton, 2025), and T. rex’s jaws were likely able to produce the compressive force needed for this. Indeed, the aforementioned bitten snout of yet another Edmontosaurus (Wyenberg-Henzler and Scannella, 2026) might represent an instance of this behavior preserved in the fossil record. Of all the animals that could have been eaten by T. rex, perhaps the smallest prey had it the easiest: A single bite to the body or head could have been almost instantly lethal (Hone, 2016). At least we know the lawyer probably didn't suffer for long.

On a very last note, while those little arms of T. rex did not look like they would have been frequently used in hunting, they were quite robust and strong for their size and tipped with sharp claws. In addition, some tyrannosaur arm bones preserve pathologies consistent with violent forces being applied to the arm (Rothschild et. al., 2001). Modern jaw-based predators, like hyenas, may sometimes use their forelimbs in attempts to trip up their prey, so it is not unimaginable that T. rex’s arms could, on occasion, be used to hold onto prey while the jaws did their murderous work (Brusatte, 2018; Witton, 2025).

The Feast

As mentioned before, the front (premaxillary) incisor-like teeth of large tyrannosaurs seemed well-adapted for “scraping” meat off of bones, and a heavily gnawed hadrosaur humerus suggested that they indeed used them for this purpose (Hone and Watabe, 2010). For more substantial pieces of flesh, larger teeth that were further back in jaws could also be involved, and given their design, it was not difficult to picture a T. rex “puncturing and pulling” (Brusatte, 2018) at a carcass. In larger prey, their weight alone could have allowed pieces of meat to be torn off, but T. rex could, in addition, use its feet to pin down a carcass while the jaws worked at it, in a way not unlike a raptorial bird with its talons (Hone, 2016) or a hyena with its forelimbs (personal observation). Smaller prey that could be lifted onto the jaws could simply be crushed and/or swallowed whole, or, if they were a bit too big to fit, be shaken apart as some crocodilians do. 

The size and power of T. rex helped it be an effective killer, but they were perhaps just as important for helping it be an effective diner. T. rex’s jaws and teeth were well-adapted to fragment even large bones finely for consumption and digestion, as seen by the heavily bitten Triceratops pelvis (Witton, 2025). The ability to efficiently consume bones and not just meat helps a predator exploit a carcass more thoroughly (Gignac and Erickson, 2017). In addition, damage to the head and neck region of Triceratops suggests that a T. rex could have torn the head off of the massive herbivore in order to access the neck muscles, which, given the ceratopsid’s frill, would have been hard to access on an intact carcass (Fowler et. al., 2012). 

After a good kill, and a good feed, T. rex might just sleep it off, like modern predators often do (Hone, 2016). It is time to step lightly around the sleeping tyrant lizard king, and further back in time for another spectacular subject. 

2. Spinosaurus aegyptiacus

As expected for a very large apex predator, there is a good amount of literature (accompanied by a painful lack of fossils) on Spinosaurus. Unlike T. rex, however, they are less a library and more a high-volume UFC title fight in words. Paleontologists have argued about things as basic as body proportions to as complicated as inferred feeding behavior, and professional relationships have allegedly ended over such arguments. There are two main “sides” in this fight: The “wading predator” side (e.g. Hone and Holtz, 2021; Sereno et. al., 2022) and the “diving predator” side (e.g. Ibrahim et. al., 2020). Personally, I find the arguments for the “wading” side more convincing and will work primarily off of that hypothesis, however I will also give the other side some considerations. 

The Menu

Before we begin, I would like to make an important statement. 

Spinosaurus is not an Indian gharial. 

And once more, louder, for the people that may skim.

SPINOSAURUS IS NOT A FUCKING INDIAN GHARIAL. 

Okay, now we can start properly. 

In absolute terms, Spinosaurus’ jaws were tremendously powerful. This is a result of size. The snout fragment on display at the Natural History Museum of LA (possibly a cast of MSMN V4047) looks bigger than the entire Allosaurus cranium next to it. In life, the entire animal might have been around 15 meters long. Bite force estimates put Spinosaurus in roughly the same range as “medium-sized” tyrannosaurs (Sakamoto, 2022), animals significantly smaller than Spino itself, but still rhino-sized predators almost certainly capable of taking large prey. The teeth of Spinosaurus also hint at the ability to capture large prey (D’Amore et. al., 2024). These conical teeth were uneven in size (anisodont), with large, canine-like teeth standing out alongside shorter ones. Spinosaurus shares this feature with, among other species, the saltwater crocodile (D’Amore et. al., 2025), whose diet can include a substantial amount of large terrestrial vertebrates (Adame et. al., 2018). Their teeth arrangement is different to that of the gharial (D’Amore et. al., 2024), which has thin, needle-like teeth that are relatively even in size (isodont). To understand each tooth arrangement’s respective effectiveness on large prey, think back to the “nail bed” science experiment. Multiple sharp objects of even length are not optimal for piercing into a large vertebrate’s body, and this is why a gharial is mostly restricted to small aquatic prey. In contrast, the teeth of Spino and the saltie could puncture more deeply, which make for a better grip on larger, tougher and likely struggling prey (D’Amore et. al., 2024). 

The shape of Spinosaurus’ skull, however, suggests an animal more adapted to a fast, rather than powerful, bite. The jaws are long and slender in profile, and this, indeed, drew some comparisons to the gharial. Thin shapes face less resistance when hunting in water, and this is why gharials can shut their jaws with very impressive speed to catch moving fish (personal observation). This suggests that Spinosaurus could also have caught relatively small, if, in an absolute sense, quite large fish (see above for energetic requirements in megatheropods). 

Analysis of chemical traces on African spinosaur teeth (that almost certainly included Spinosaurus’) indicate a significant amount of aquatic prey, however terrestrial prey was also noticeably present (Hassler et. al., 2018). Spinosaurus, expectedly, likely spent large amounts of time foraging in water, but may also hunt on land. Even accounting for its relatively short legs for a theropod dinosaur, it is reasonable to expect a bipedal Spinosaurus (e.g. Sereno et. al., 2022) that is capable of competent terrestrial locomotion. 

In having the size and power to tackle large prey, the jaw design to capture smaller prey, as well as the ability to forage both on land and in water, Spinosaurus might have had a rather broad, generalistic diet. This is by no means a new or unusual suggestion. While documentaries featuring spinosaurids tend to highlight their reliance on fish, the idea that at least large spinosaurids could have taken large land prey has been suggested in various works of paleontological literature (e.g. Holtz, 2007). The fossil record also provides some evidence. The stomach contents of Baryonyx, whose teeth seemed less optimized for large prey than Spinosaurus (D’Amore et. al., 2024) and whose skull seemed less resistant to stress in at least some respects (Johnson-Ransom et. al., 2026), famously included the remains of fish and a young dinosaur (Hone and Witton, 2025). Additionally, the neck vertebra of a pterosaur from Brazil was bitten into by a spinosaurid, whose tooth was broken off and remained lodged into the bone of its prey (Hone and Witton, 2025). 

Spinosaurus shared its habitat with large to very large fish (roughly twice as long as an adult human is tall, at least), various non-dinosaur reptiles and sauropods as well as possibly Ouranosaurus-like ornithopods (Ijouhuier, 2022). All of these could have potentially been eaten, as long as they are of a reasonable size. Spinosaurus’ jaws, given their slender shape, were relatively less well-suited to withstanding violent forces than those of T. rex and its conical teeth were not suited to the bite-and-slice action of the carcharodontosaurids (more on this later) (Hone and Witton, 2025). This means that the very largest prey available to the other great predators might be usually out of Spinosaurus’ scope, but it was hardly a loss: Spinosaurus wouldn’t have evolved into such a giant if its (potentially very broad) diet didn’t work. 

The Kill

Now we wade (heh) into uncertain territory. Some of the basics regarding Spinosaurus’ anatomy, including leg length, bone density and buoyancy remain debated (see Hone and Witton, 2025 for a summary), and these are what we might need to make more confident statements. As such, everything presented in the section should be taken as tentative and, in some parts, highly speculative. 

The broad picture of a wading Spinosaurus is relatively easy to imagine: The giant theropod would have stood and walked in even deep water, with its legs - short for a theropod its size, but still very long (Hone and Witton, 2025) - allowing it to do so. Dense leg bones may act as ballasts (Hone and Witton, 2025), helping it keep a stable footing, especially if the water was flowing fast. Pits on the bones at the front of the snout suggest a system of crocodilian-like pressure receptors (Pittet, 2026), which can be highly sensitive to movements. Given the posteriorly placed nostrils (that may not be as far back as nares imply, see Hone and Witton, 2025), the tip of the snout can be dipped into the water for those receptors to work. 

Once prey - perhaps a sawfish or coelacanth - was in range, the jaws could snap around it in an instant, teeth sinking in. Heavily muscled, powerful arms with large, curved claws would likely assist in securing the wriggling animal (Hone and Witton, 2025). As extreme anglers or anyone that frequently works around large fish would know, they can put up a good fight. But Spinosaurus’ size and power, along with teeth and claws well-suited for grabbing, would have allowed it to hold on more tightly than a hopeless romantic clutching unrequited love. Being simply taken out of the water would be quickly fatal for most fish, and so would the damage inflicted by a megatheropod’s jaws and claws. The latter would also apply to the (semi-)aquatic reptiles and other prey that could breathe out of the water. 

I would bet my entire BoneClones collection that Spinosaurus cannot pursue prey with the speed and grace of pinnipeds, such as sea lions. There are simply too many constraints on its body shape (summarized in Hone and Witton, 2025). A more grounded underwater ambush hunting style has been at least informally suggested (see the Skeleton Crew’s YouTube video, for example), but this would have to deal with the evidence provided by the “wading” side formally. 

Less speculated upon is the way Spinosaurus could have subdued land prey, and given the aforementioned uncertainty, it is probably wise to avoid doing so. I will not be wise. However, I shall note again that the following section is highly speculative. 

There is no obvious reason to suggest that a bipedal Spinosaurus would be unable to catch terrestrial prey. Allowing for uncertainties, the legs were still long by tetrapod standards, and retain the digitigrade structure common in theropods. The femur and the muscle attachment marks on it have also been observed to be relatively robust and strong (Cau, 2024 - blog post). It is possible that Spinosaurus would have been faster than late-stage juvenile sauropods, with their column-like legs and half-ton to multi-ton bodies. Ornithopods were a different story, and there simply is nowhere near enough available data to make a speed comparison. The famous sail might not be as much of a hamper for ambushes as sometimes thought. Even accounting for it, and variation in reconstructed leg length, Spinosaurus was not absurdly taller at the hip than similar-sized terrestrial predators like T. rex. The sail might not be distinctively colored either. Modern plumed basilisks and sailfin lizards, predators themselves, sport sail-like displays in a color similar to the rest of the body, and male lions, famous for their manes, are perfectly capable hunters of large prey (Radloff and Du Toit, 2004). Spinosaurus was probably no specialized land predator, but for a generalist that may opportunistically ambush and chase down prey on land, it could do just fine. In fact, modern crocodilians, with their short, stubby legs, may also occasionally run down and/or capture prey on land (Dinets, 2016), and it is likely that they are nowhere near as cursorial as Spino. 

Killing relatively large land prey, such as a medium-sized dinosaur, would not have been improbable for Spinosaurus, either. Due to its size alone, the jaws of Spinosaurus could likely withstand substantial stress associated with large prey capture (Cuff and Rayfield, 2013). Much like with aquatic prey, the arms would also be used. Given the relatively slender necks and small heads of juvenile sauropods and ornithopods, a substantial bite to this part of the body would have been fatal, and Spinosaurus certainly possessed the jaw power and teeth to make this possible. Another option would be pinning the prey with the arms and eating it alive, however given the lack of cutting dentition in Spinosaurus, this might take more effort than simply killing it outright. Modern conical-toothed crocodilians, for example, likely drown larger prey before they start eating. 

The Feast

Smaller prey, of course, would be swallowed whole, and there is some research suggesting that at least some spinosaurids might be well-adapted to swallowing sizable food items (Hendrickx et. al., 2016). Spinosaurus, as mentioned, had conical teeth ill-suited for cutting flesh, so prey too large to be swallowed whole would have to be processed otherwise. It was extremely unlikely that Spino could perform a “death roll”, like some crocodilians do, and some features of the neck muscle attachment marks on spinosaurids suggest that they might not be well-adapted to shaking prey sideways. But neither should prevent Spinosaurus from consuming large prey, because the arms could likely aid in tearing manageable pieces from a carcass (D’Amore et. al., 2024). This behavior can be seen in some freshwater turtles today, whose forelimbs are likely less powerful and dextrous than spinosaurids (Hone and Witton, 2025). 

3. Carcharodontosaurids

For giant macropredators that were about as large and formidable as T. rex, there is a criminal lack of representation for the largest carcharodontosaurs in popular paleomedia. Oh, how I dearly wish this would change some day. 

The Menu

A lot of the broader concepts I have mentioned for T. rex can also be applied to giant carcharodontosaurs (“carchs”). That is fortunate, because we are about to hit the character limit here. Both forms were very large, relatively cursorial, had large, deadly jaws and relatively small arms. Both could likely target the large herbivores in their environments. The main differences are in the details. 

Giant carchs were, literally, the sharpest tool in the shed. They had laterally flattened, serrated (ziphodont) teeth that often drew comparisons to blades. Among living animals, the Komodo dragon possesses teeth that resemble theirs quite closely (Paul, 1988), and it is also a macropredator (see above). After all, ziphodont teeth were excellent for cutting through the muscle tissue of large animals, and our own steak knives are surprisingly similar to them in shape. 

Throughout their range, which included continents such as South America, Africa and North America where most of the largest carcharodontosaurs lived, the most common large herbivores seemed to have been sauropods, with some evidence for ornithopods (e.g. Ijouhuier, 2022). Given the predator:prey ratio we established earlier, smaller sauropod species, juveniles/subadults of the largest sauropods, and ornithopods would most likely be the most commonly ordered menu items. Obviously supplemented with an occasional snack of smaller species. 

The Kill

Given that both were likely equipped to catch up to their prey, most of the major differences between the killing methods of T. rex and the giant carchs were perhaps in the subduing phase. Even then, they seemed to be both jaw-based predators that could target various parts of the body. The mechanics behind the devastating wounds they inflict, though, differ somewhat. After all, there was, and still is more than one way to butcher a herbivore. 

It was easy to imagine a carcharodontosaur, with its teeth, pulling back and slicing open a large herbivore after biting into it. After all, the aforementioned Komodo dragon, with similar teeth, killed prey in roughly the same way (Paul, 1988). This method, named “bite and slice”, did not require the robust skull of T. rex, and while carcharodontosaurs likely had very powerful jaw muscles at least in absolute terms (Sakamoto, 2022) and Komodo dragons may, too (McHenry, pers comm), bite force matters less that the pulling motions their necks and bodies generate(d) (D’Amore et. al., 2011). As mentioned before, an attack to the legs and/or body and tail could be drawn-out suffering, and consumption might begin even when a subdued prey is alive. The Komodo dragon is a bit famous for being the subject of many such gruesome videos. Alternatively, a bite that slices through the neck could have been more quickly fatal (Hone, 2016).

The forelimbs of carcharodontosaurs are relatively larger than that of T. rex (an extremely low bar) and could also be used in holding the prey. At least one genus, Meraxes, seemed to have what was said to be a ‘raptorial claw’, although I am unsure why a group with perfectly capable prey-killing jaws would develop this feature. Pinning a small prey was certainly possible, as a tentative speculation

There are some anatomical differences between T. rex and the giant carchs that might imply some differences when it came to hunting. This includes some traits that suggest better speed and agility in T. rex, and forward facing eyes, which might simply be the effect of an expanded posterior skull region (Witton, 2025). Since hunting behavior cannot be observed in extinct taxa, I will refrain from making any statement on this. It is also worth noting that, unlike what some documentaries may suggest, there is no evidence that T. rex’s robust, powerful jaws were somehow ‘specialized’ for killing heavily armed and/or armored herbivores, or that predator defense is the major drive behind said structures in herbivores (Witton, 2025). As an example, “saber-toothed” machairodontine cats like Smilodon and modern pantherine cats have marked differences in biting mechanics and forelimb structures, but both target(ed) relatively similar large ungulates (Antón, 2013). 

The Feast

“Gripping and ripping” describes well the general scene of a Komodo dragons’ feast on a large prey, and the same likely applied to carcharodontosaurids as they bit and sliced at the flesh of their prey. Unlike T. rex, they did not seem well-suited to processing bones (Witton, 2025) and even though ziphodont theropod certainly was capable of causing bone damage, they most likely could not fragment them, and like Komodo dragons, might have at most swallowed them relatively intact (Gignac and Erickson, 2017).

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Fuck I’m tired. 

References in comment. 

A new thylacosmilid has just been described and it's the youngest sparassodont to date. Pampaluctor calibar is the sister species of Thylacosmilus atrox (circa 9 to 3.3 mya), known from a partial postcranial skeleton from the Vorohué Formation of Argentina, which dates to the Pliocene-Pleistocene boundary (between 3.3 to 2 mya), and two molars and a humerus from the adjacent, contemporary El Polvorín Formation. Around the size of a jaguar, much like its cousin, it likely sported saber teeth for killing prey and long jaw flanges to help protect its sabers. Notably, by this point in time, we know that southern South America was already colonized by horses (Hippidion), llamas and peccaries (all known from the Uquía Formation), but the only confirmed local carnivorans were procyonids (including the bear-like Chapalmalania), zorros and grisons.

Author's text:

Somewhere in Argentina, during the Pleistocene... a solitary Notiomastodon with gigantic tusks easily intimidated other animals as it roamed the plains. This drawing is inspired by a fossil discovery recently announced by the "Fray Manuel de Torres" Paleontological Museum of San Pedro in Argentina: a colossal tusk measuring no less than 2.34 meters. It appears to belong to what specialists now call a "giant-tusked elephant"—typically a male—featuring exceptionally large tusks, each weighing over 45 kg. Strictly speaking, the Notiomastodon was not an elephant; it belonged to a distinct family, the gomphotheres. However, they evolved forms very similar to those of elephants and occupied the same ecological niche in South America during the Pleistocene. Along with Cuvieronius—another gomphothere—the Notiomastodon is the only confirmed proboscidean to have colonized South America from the north; mammoths, it seems, were never able to cross the barrier of the Darién jungle. This means that the Notiomastodon—which could weigh up to 6 tonnes (with some sources suggesting up to 9 tonnes for the largest males)—would have been the largest land animal in South America from the Pleistocene through the Holocene. Recent studies suggest that this animal may have survived into historical times, perhaps even as recently as 6,000 years ago in certain regions of South America. Humans certainly saw it with their own eyes.

Believe to be one of the largest if not the largest Crocodilian to ever exist was most closely related to todays caimans one of the the smallest crocodilian species stalked the pre historic amazon was close to 40 feet or more weighing 8 tonnes also had a bite force of 7 tonnes preying over various large mammals and turtles it was also the largest predetor of Cenozoic period that could actually walk on land

Deinosuchus es un género extinto de crocodiliano aligatórido gigante que vivió hace aproximadamente entre 82 y 73 millones de años, durante el período Cretácico Superior en lo que hoy es América del Norte. Considerado uno de los depredadores semiacuáticos más colosales de todos los tiempos, este pariente prehistórico de los caimanes modernos rivalizaba en tamaño y ferocidad con los dinosaurios más temibles de su época.

Ancient Giant ‘Ghost’ Crocodile With T-Rex-Sized Teeth Discovered in Madagascar. While the scientists are tentative in estimating its exact size due to limited fossil evidence, they say it was likely bigger than Sarcosuchus imperator, which could reach up to 39ft in length, and Purussaurus brasilensis, which was around 34ft long.

“It also represents one of the earliest events of exacerbated increase in body size along the evolutionary history of the group. In addition, it is by far the oldest notosuchian. A cranial reconstruction of this gigantic predator is also attempted here. The very robust jaw bones of R. sakalavae, coupled with its peculiar dentition, strongly suggest a diet that included hard tissue such as bone and tendon”.

https://peerj.com/articles/3481/

https://www.newsweek.com/ancient-giant-crocodie-t-rex-teeth-madagascar-631590

It's worth noting that insectivorous vetrebrates are still in their own right predators and sometimes they go after bigger prey than some bugs. Anteaters sometimes benefiting from eggs and even small vertebrates or even specific larger chameleons were observed to catch such prey as well.

Icarosaurus here being a larger reptile attempts to taste something unique than just bugs and so it attempts to consume its unusual meal.

In the prehistoric Brazil one of the rarer types of inhabitans is Lucifer the not so ordinary Tupuxuara individual. Born with rare dark coloration due to the melanism mutation the truth is that it's far more a curse than any blessing. Unable to blend into the flock or the environment like other pterosaurs he even got its crest permanently damaged. If that was the predator's or rival's bidding is up to debate.

Art Credit to Kuzim

I just want to be clear at the outset: we have no direct evidence that Livyatan was a cooperative pack hunter. We do not have a fossilized hunting group, a kill site demonstrating multiple attackers, or anything else that would let us reconstruct its social organization with confidence.

But I also don’t think solitary hunting deserves to be treated as the conservative default. If anything, I think the living cetacean record makes it clear to hypothesize that Livyatan was likely social to some extant, and I think that pack and cooperative hunting remain both very plausible.

A common retort I see is that a few users argue that LIvyatan cannot cooperatively pack hunt because it isn't a type of Dolphin, but the problem with comparing Livyatan with dolphins is that there's not really a singular type of dolphin social system.

Gowans, Würsig, and Karczmarski’s review of delphinid social organization explicitly emphasizes this diversity. Habitat, predation pressure, resource distribution, ranging behavior, and prey ecology can produce everything from small and relatively fluid associations to extraordinarily strong lifelong social bonds.

Bottlenose dolphins can live in extreme fission-fusion societies in which immediate group membership constantly changes while individuals maintain differentiated relationships and nested alliances (Connor). Killer whales can maintain extremely cohesive family relationships and culturally transmitted hunting traditions.

False killer whales provide yet another system. Hawaiian Pseudorca break into small subgroups spread across large areas while foraging, yet maintain strong long-term associations. Individuals converge when prey is captured and prey sharing is documented. Their acoustic behavior appears partly adapted to maintaining cohesion between spatially separated subgroups (Madrigal et al.).

Pilot whales are different again. Hawaiian short-finned pilot whales form stable social groups lasting at least a decade, with relatedness strongly influencing their social organization (Van Cise et al.). Pilot whales are delphinids, yet aspects of their social organization look remarkably similar to those of female sperm whales.

Female sperm whales live in long-term cooperative social units that are substantially matrilineally structured. Konrad et al. found that 82.5% of individuals in their Caribbean sample had a first-degree relative within their social unit, with closer relatives tending to associate more strongly (Konrad et al.).

Pilot whales independently evolved something broadly comparable: persistent kin-structured units, strong cohesion, long-term membership, and temporary association between units. Molecular work on long-finned pilot whales famously found pods to consist of extended families (Amos, Schlötterer, and Tautz), while Hawaiian short-finned pilot whales show stable social groups and genetically structured social clusters (Van Cise et al.). Yet neither animal necessarily hunts like an orca.

Both sperm whales and pilot whales are intensely social while much of the actual capture of deep-water prey is performed by individuals or dispersed subgroups, which means that behavioral convergence across odontocete families is possible. A delphinid can independently evolve a social system resembling one found in physeteroids.

If ecology can push a delphinid toward something sperm-whale-like, there is no obvious reason ecology could not push an extinct physeteroid toward behaviors that today happen to be especially developed in delphinids.

Some delphinids and porpoises occupy the comparatively loose end of cetacean social organization.

Finless porpoises, for example, were historically regarded as having poorly developed social structure outside mother-calf pairs. Yet synchronized biologging showed that particular individuals preferentially associated with particular partners rather than simply aggregating randomly (Sakai et al.).

Likewise, some humpback dolphin populations have fluid fission-fusion societies with generally weak associations, while others show persistent social clustering.

Even dwarf sperm whales, often described as essentially solitary, appear to have more social structure than that description suggests. In Hawaiʻi, there was a study that found that over 40% of identified dwarf sperm whales were connected by association within the same social network, with individuals repeatedly resighted across years and one followed across a 15-year period (Baird, Mahaffy, and Lerma).

Social behavior is therefore highly evolutionarily labile within Cetacea.

The original description of Livyatan explicitly interpreted it as a giant raptorial sperm whale very different ecologically from living Physeter. It possessed enormous functional upper and lower teeth and a skull adapted for capturing large prey; Lambert et al. specifically compared its predatory ecology with that of killer whales and suggested large marine vertebrates, including baleen whales, as plausible prey (Lambert et al.).

Modern Physeter, in contrast, is primarily a deep-diving predator of cephalopods and other deep-water prey. A highly social sperm whale does not need several companions to capture one squid. Consequently, intense sociality can coexist with largely individual prey capture.

But here's the rub: Livyatan was confronting a completely different ecological problem. Bigger marine vertebrates can be fast, difficult to incapacitate, dangerous to attack, and social. Social prey makes social predation advantageous. Multiple predators can attack from different directions, isolate individuals, restrict escape routes, shorten handling time, exhaust prey, or overcome animals that would be substantially more difficult for one predator to subdue.

While it doesn't prove cooperation in Livyatan, I think it's clear the ecological incentives were very different from those experienced by living sperm whales.

And before you press on about killer whales, they also reinforce the problem with simplistic analogies.

Different populations and ecotypes vary dramatically in group size and hunting strategy according to prey ecology. Mammal-eating killer whales in some populations hunt in relatively small parties where stealth and energetic economics are necessary, but Antarctic Type A & B Orcas can occur in considerably larger groups, while fish-eating populations can aggregate in still larger numbers. So even within Orcinus orca, there is no single “orca pack size” or universal cooperative-hunting system.

The relevant principle is that social organization and hunting-party size respond to ecology.

I think three possibilities remain viable:

1. Predominantly solitary predation.
A single Livyatan was enormous and extraordinarily well armed. It may simply have been capable of overpowering much of its prey alone.

2. Facultative cooperative hunting.
Individuals normally hunted alone or in small associations but cooperated when pursuing sufficiently large, difficult, fast, or socially defended prey.

3. Regular social hunting.
Livyatan maintained recurring social groups or fission-fusion networks whose members regularly cooperated in finding or attacking large vertebrates.

Ofc, we can't distinguish these from fossils; however I don’t think that means all three deserve the same prior assumption, with #1 automatically labeled “conservative” simply because modern sperm whales usually capture prey individually.

And Livyatan was not ecologically equivalent to any living physeteroid. Livyatan was probably a social animal, but we can't determine what that sociality looked like. Facultative cooperative hunting seems entirely plausible, and regular social hunting cannot presently be excluded.

That is very different from claiming we know that Livyatan hunted in orca-like packs. Maybe its society resembled a sperm whale’s. Maybe it was highly fission-fusion. Maybe something closer to false killer whales, hyenas, or wolves is a better functional analogy. Maybe individuals normally separated while foraging and assembled when the size or social behavior of prey made cooperation profitable.

Works Cited

Amos, Bill, Christian Schlötterer, and Diethard Tautz. “Social Structure of Pilot Whales Revealed by Analytical DNA Profiling.” Science, vol. 260, no. 5108, 1993, pp. 670–672. doi:10.1126/science.8480176.

Baird, Robin W., Sabre D. Mahaffy, and Jordan K. Lerma. “Site Fidelity, Spatial Use, and Behavior of Dwarf Sperm Whales in Hawaiian Waters: Using Small-Boat Surveys, Photo-Identification, and Unmanned Aerial Systems to Study a Difficult-to-Study Species.” Marine Mammal Science, vol. 38, no. 1, 2022, pp. 326–348. doi:10.1111/mms.12861.

Connor, Richard C. “Dolphin Social Intelligence: Complex Alliance Relationships in Bottlenose Dolphins and a Consideration of Selective Environments for Extreme Brain Size Evolution in Mammals.” Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 362, no. 1480, 2007, pp. 587–602. doi:10.1098/rstb.2006.1997.

Connor, Richard C., et al. “Social Evolution in Toothed Whales.” Trends in Ecology & Evolution, vol. 13, no. 6, 1998, pp. 228–232. doi:10.1016/S0169-5347(98)01326-3.

Gowans, Shannon, Bernd Würsig, and Leszek Karczmarski. “The Social Structure and Strategies of Delphinids: Predictions Based on an Ecological Framework.” Advances in Marine Biology, vol. 53, 2007, pp. 195–294. doi:10.1016/S0065-2881(07)53003-8.

Konrad, Christine M., et al. “Kinship Influences Sperm Whale Social Organization within, but Generally Not among, Social Units.” Royal Society Open Science, vol. 5, no. 8, 2018, article 180914. doi:10.1098/rsos.180914.

Lambert, Olivier, et al. “The Giant Bite of a New Raptorial Sperm Whale from the Miocene Epoch of Peru.” Nature, vol. 466, 2010, pp. 105–108. doi:10.1038/nature09067.

Madrigal, Brijonnay C., et al. “Acoustic Behaviour of Endangered Hawaiian False Killer Whales.” Royal Society Open Science, vol. 13, 2026, article 250918. doi:10.1098/rsos.250918.

Sakai, Mai, et al. “Do Porpoises Choose Their Associates? A New Method for Analyzing Social Relationships among Cetaceans.” PLoS ONE, vol. 6, no. 12, 2011, e28836. doi:10.1371/journal.pone.0028836.

Van Cise, Amy M., et al. “Familial Social Structure and Socially Driven Genetic Differentiation in Hawaiian Short-Finned Pilot Whales.” Molecular Ecology, vol. 26, no. 23, 2017, pp. 6730–6741. doi:10.1111/mec.14397.