"Grapple and slash" predators are not (really) a thing

[Infinity Blade]

The subject of this post is very niche and specific, even within zoology, but I wanted to make a post about it anyway. In an excellent work rebutting the obligate scavenger hypothesis put forth for Tyrannosaurus rex, Thomas R. Holtz Jr. alludes to three different modes of predation supposedly employed by modern predatory vertebrates, which are named in an old 1995 post on the Dinosaur Mailing List (link->). These are as follows:

1) Grapple-and-slash. Best typified by modern felids (cats), these are predators characterized by highly compressed, recurved, blade-like claws on the hands and feet; relatively short and powerful limbs; and tails used as dynamic stabilizers to allow for quick turns. Grapple-and-slash predators are for the most part ambush predators, which seize the prey with the forelimbs after a very short chase. The prey is then dispatched with a combination of slashes from the forelimb, disemboweling kicks with the hindlimb, and bites and/or suffocation with the mouth. Grapple and slash predators are not particularly fast in the long run, but are good for short acceleration. [And for some reason, Jack Horner seems to think that this is the preferred form of predation, despite it being limited today to only one major group, the Felidae].

2) Grapple-and-bite. Best typified by modern raptorial birds, these are predators characterized by claws which are curved but fairly round in cross-section. These claws are at the end of fairly powerful limbs. Grapple-and-bite predators today are for the most part ambushers ("death from above"), which seize the prey with the forelimbs, dispatching the prey with bites to the neck or back, and flying away with the carcass to eat elsewhere. The claws are used primarily for holding prey, while the jaws are the main killing tool.

3) Pursuit-and-bite. Typified today by canids (dogs, wolves, etc.), hyaenids, the cheetah, and in the recent past by flightless predatory birds. The claws of pursuit-and-bite predators are for the most part not highly curved and are rounded in cross-section. These predators do have powerful jaws and necks, long teeth, and relatively long limbs. Pursuit-and-bite predators characteristically run down their prey after a fairly long chase, seize the prey in their jaws, and kill the prey with a combination of biting and suffocation. The claws, if used at all, are used to stabilize the victim so the jaws can do their work.

Most of this sounds about right. Predators that grapple and bite their prey are indeed a thing, as are predators that chase their prey and use primarily (if not solely) their jaws. But…grapple and slash? Is that really a thing? Only two families of predatory tetrapod (Felidae and Dromaeosauridae) are claimed to belong to this category, and in short, neither of them really do.

As is widely known among paleontologists and paleontology enthusiasts at this point, the hypertrophied second digit pedal claws of dromaeosaurid are no longer thought to be primarily slashing tools (Manning et al., 2005; Fowler et al., 2011; Bishop, 2019). In fact, if one thinks about “Raptor Prey Restraint”, the dromeosaurid’s method of killing (small) prey is to pin down the prey item with the hindlimbs, use the forelimbs for stability flapping, and dispatching it with the jaws (Fowler et al., 2011). Although the sickle claw is often proposed to be the primary weapon of dromaeosaurids (and the jaws the secondary weapon), dromaeosaurid snouts are convergent with those of canids (which rely solely on their jaws for predation) in that they exhibit the same adaptations for prey of certain size. This further suggests that in fact, it is the other way around: the jaws of dromaeosaurids were their primary weapons (Powers, 2020).

The snout dimensions of eudromaeosaurian taxa do fall into three categories like modern canids but it would be useful to examine the skull morphologies through use of models just as Slater et al. (2009) did with canids. If canids really do represent a good analog for dromaeosaurids regarding snout dimensions, it would be expected that FEA models would corroborate each other as well. The raptorial claw in dromaeosaurids is another morphology worth looking into. This feature has been proposed by some authors to be the primary weapon of these animals, the muzzle being the secondary weapon. The results of this thesis would argue the opposite as the dimensions of snouts of eudromaeosaurians show similar disjunct separations as in modern canids, which do not have raptorial claws and rely almost exclusively on their snouts for handling prey. The raptorial claw of dromaeosaurids may have allowed them to acquire larger prey than would have been the norm in extreme situations such as with the ‘fighting dinosaurs’ specimen (Barsbold 2016). Or it may have provided a useful tool to hold or tear at incapacitated prey (Manning et al. 2009, Fowler et al. 2011). Morphometric analysis presented in this thesis and in other studies has offered a useful way to examine both taxonomic and functional morphologies.

This mode of predation sounds an awful lot like the “grapple and bite” mode of predation instead. Safe to say, this is the group dromaeosaurids truly belong to.


So what about cats? It is certainly true that cats will rake rivals with their pedal claws, but sometimes one will read about how cats will kill prey with lacerating/disemboweling kicks from the claws on the hind feet (like above). One study even said that the hind foot claws of felids were more “blade-like” than the more hook-like claws on the front paws (Bryant et al., 1996).

However, such incidents are very, very, VERY rare. This is the only incident I am aware of where a felid ever disemboweled a living prey item with its pedal claws. Even then, in my own personal communications with Dr. Craig Packer, a lion biologist, he suggested that this was an accident (and that the lion was instead likely going for a bite). Far, FAR more common is grappling the prey and administering a suffocating/skull crushing/vertebra snapping bite.



Likewise, zebra wounds tend to be more severe than in other ungulates, enough to expose muscle and extend up to 60 cm in length (Plumb & Shaw, 2018), suggesting zebras are unusually vulnerable to clawing (and thus not representative of the damage felid pedal claws will cause to most prey items).

What are felid pedal claws actually like? Bryant et al. (1996) correctly note that they are generally less curved than the manual claws. But are they more blade-like? Well…no. In fact, they tend to not just be less curved, but also often blunter, broader, and less robust than the manual claws. The grasping mechanism on the pedes is also said to be less developed than that of the manus (see below).


Here are some descriptions for various felid species. The hind claws of a leopard are “smaller [than the front paws’] and not so sharp”.


The caracal’s pedal claws are broader and less curved than the manual claws.


The pedal claws of the sand cat are less compressed, weakly curved, more elongated, and relatively blunt. Even the retractile mechanism is said to be kind of poorly developed.

Source for the above four excerpts: Geptner (1988)

The pedal claws of the cougar are, again, not as recurved, robust, or sharp as the manual claws (Logan & Sweanor, 2001).


The pedal claws of the ocelot are said to be slightly blunted due to coming into more contact with the ground (Fayrer, 1875).


And predictably, the domestic cat’s manual claws are sharper than its pedal claws (Armes, 1900).


Here are some visual representations. This is the hind foot of a captive 6 year old female tiger (Arencibia et al., 2019). Notice how blunted and not very curved the claws are.


Here’s the hindlimb of a lion compared with that of a spotted hyena (Castelló, 2020). Again, the pedal claws are not particularly curved or pointy. Compare these with the claws of the hyena, which are just blunt cleats; the comparison would be much starker if this showed the front paw claws instead.


From the same source as above, here’s the skeleton of a domestic cat. Again, compare the manual and pedal claws.


Hell, compare those pedal claws to any of the claws of this aardwolf. All elongated, only moderately curved, somewhat pointed but not needle sharp.


Wait, am I comparing the pedal claws of cats with the blunt claws of…hyenas (and by extension dogs)? Yes. In fact, I'm not the first person to->. Sure enough, some of the sources above state that the pedal claws of cats are used for traction, bracing, and climbing. Although they can certainly be co-opted as weapons, they’re not specialized raptorial tools the way the manual claws are. “Blade-like”? Hardly. Cat pedal claws are cleats, not blades.


So in conclusion, both “grapple and slash” predators were/are not so. Both cats and dromaeosaurids, in fact, firmly fit within the “grapple and bite” category, leaving nothing within the proposed “grapple and slash” category.

[Creodont]

IIRC Megaraptor unguals had keels. Even if not designed specifically to tear or slice, it would make them the best potential slashing claws (if push came to shove) out of any animal I can think of.

[Infinity Blade]

Jun 2, 2023 23:40:54 GMT 5 Creodont said:

IIRC Megaraptor unguals had keels. Even if not designed specifically to tear or slice, it would make them the best potential slashing claws (if push came to shove) out of any animal I can think of.

Multiple species with raptorial claws have keels on them. The ability to cut is probably a side benefit of these keels, although they're probably primarily there to help the claw puncture skin and flesh. However, the point I wanted to make here is that even though some claws are better at cutting than others, no predator really goes out of its way to slash its prey to death like described above. Any predatory claw's first purpose is to grip onto prey, while another organ (the jaws) kills it (although, some predators like eagles have hypertrophied talons for their size, and it's probably their ability to create deep puncture and gouging wounds that allows them to severely wound large prey with only/mostly the claws).

[theropod]

Jun 1, 2023 5:53:11 GMT 5 Infinity Blade said:

1) Grapple-and-slash. Best typified by modern felids (cats), these are predators characterized by highly compressed, recurved, blade-like claws on the hands and feet; relatively short and powerful limbs; and tails used as dynamic stabilizers to allow for quick turns. Grapple-and-slash predators are for the most part ambush predators, which seize the prey with the forelimbs after a very short chase. The prey is then dispatched with a combination of slashes from the forelimb, disemboweling kicks with the hindlimb, and bites and/or suffocation with the mouth. Grapple and slash predators are not particularly fast in the long run, but are good for short acceleration. [And for some reason, Jack Horner seems to think that this is the preferred form of predation, despite it being limited today to only one major group, the Felidae].

2) Grapple-and-bite. Best typified by modern raptorial birds, these are predators characterized by claws which are curved but fairly round in cross-section. These claws are at the end of fairly powerful limbs. Grapple-and-bite predators today are for the most part ambushers ("death from above"), which seize the prey with the forelimbs, dispatching the prey with bites to the neck or back, and flying away with the carcass to eat elsewhere. The claws are used primarily for holding prey, while the jaws are the main killing tool.

3) Pursuit-and-bite. Typified today by canids (dogs, wolves, etc.), hyaenids, the cheetah, and in the recent past by flightless predatory birds. The claws of pursuit-and-bite predators are for the most part not highly curved and are rounded in cross-section. These predators do have powerful jaws and necks, long teeth, and relatively long limbs. Pursuit-and-bite predators characteristically run down their prey after a fairly long chase, seize the prey in their jaws, and kill the prey with a combination of biting and suffocation. The claws, if used at all, are used to stabilize the victim so the jaws can do their work.

This is really a weird categorization. I would be willing to give it to them that raptorial birds, depending on the taxon, can also rely on their jaws when taking down prey, but there is no way they do this more than felids as implied by these categories.

At least for eagles, the most macrophagous of all raptors, the documented cases of classic predation (in the sense that the prey is killed during the predation event) that I know have them primarily or even entirely using their talons to dispatch the prey. I am not aware of any cases where an eagle killed something with its bite, but numerous examples of documented eagle kills where the cause of death were talon penetrations to the central nervous system or internal organs (e.g. the records of predation by golden eagles on coyotes and domestic cattle). There are instances of eagles "flesh-grazing" their prey, using their jaws to start feeding while it is still alive (such as in the well-known photo series involving a pronghorn), but if this leads to death, then it would seem to more likely be incidental (funnily enough the same thing that likely applies to cases of felids clawing their prey to death).

This is a bit different e.g. in the case of falcons (which I would still characterize as using their talons as the primary tool for predation by bludgeoning or constricting, but which also often use their beak to kill) or owls, but still, none of the raptors seem to be any more reliant on biting than cats, which pretty much invariably use their jaws to kill prey through either tracheal constriction or precision skull and nape bites.

This honestly seems rather clear-cut to me, so much so that I’m a bit baffled by how someone could classify raptors as relying more on their jaws than cats. I obviously agree with your assessment that "grapple and slash"-predators aren’t really a thing. But if they were, then I think it would be exactly reversed. Cats are clearly grapple-and-bite predators, that use their claws to subdue and control prey, and their jaws to kill it. On the other hand raptors have diverse ways in which they use their claws and beaks in predation, but seem to be almost universally less reliant on their jaws than cats, and at the extreme end of the spectrum even tend to kill entirely with their talons (even if "grapple and puncture" would be a more fitting terminology to describe them). There is simply no way an eagle is a "grapple and bite"-predator if a lion is not.

[Supercommunist]

Although I unfortunately cannot find any non-animal cruelty examples, snapping turtles are infamous for clawing prey in half they aren't able to kill it with a single bite.

[Infinity Blade]

I find it ironic how out of the predators mentioned above, it's actually the pursuit & bite predators, particularly canids and hyaenids, that slash and disembowel their prey. Obviously they do it with their teeth, but the results are absolutely gruesome, and they do it with far, FAR more regularity than clawed grappling predators. So much so that wolves, African wild dogs, and spotted hyenas have been condemned as "cruel" for utilizing such a hunting method.

Back in the Campanian and Maastrichtian, I'm sure you would've been far more likely to see a tyrannosaurid spilling the guts of its prey with its teeth than a dromaeosaurid doing so with its claws (although, the dromaeosaurid still has a long jawline filled with ziphodont teeth, so it could still do the same with its own dentition).

Jun 17, 2023 8:13:05 GMT 5 Supercommunist said:

Although I unfortunately cannot find any non-animal cruelty examples, snapping turtles are infamous for clawing prey in half they aren't able to kill it with a single bite.

This is the best alternative I could provide. Authors have written about snapping turtles biting and then ripping apart prey with their claws in the context of the wild.

...they swallow small items whole, and they hold large prey in their jaws, then rip it to shreds with their strong front claws.

www.google.com/books/edition/Wildlife_of_Virginia_and_Maryland_and_Wa/W7UxSPd2XMAC?hl=en&gbpv=1&dq=snapping+turtle+claws+prey&pg=PA403&printsec=frontcover

The forefeet and claws are used to tear larger prey into bite size pieces, and food is swallowed underwater.

www.google.com/books/edition/Amphibians_and_Reptiles_of_the_Great_Lak/hEc_DwAAQBAJ?hl=en&gbpv=1&dq=snapping+turtle+claws+prey&pg=PA177&printsec=frontcover

[Bolushi]

Jun 20, 2023 7:12:01 GMT 5 Infinity Blade said:

I find it ironic how out of the predators mentioned above, it's actually the pursuit & bite predators, particularly canids and hyaenids, that slash and disembowel their prey. Obviously they do it with their teeth, but the results are absolutely gruesome, and they do it with far, FAR more regularity than clawed grappling predators. So much so that wolves, African wild dogs, and spotted hyenas have been condemned as "cruel" for utilizing such a hunting method.

Back in the Campanian and Maastrichtian, I'm sure you would've been far more likely to see a tyrannosaurid spilling the guts of its prey with its teeth than a dromaeosaurid doing so with its claws (although, the dromaeosaurid still has a long jawline filled with ziphodont teeth, so it could still do the same with its own dentition).

Jun 17, 2023 8:13:05 GMT 5 Supercommunist said:

Although I unfortunately cannot find any non-animal cruelty examples, snapping turtles are infamous for clawing prey in half they aren't able to kill it with a single bite.

This is the best alternative I could provide. Authors have written about snapping turtles biting and then ripping apart prey with their claws in the context of the wild.

...they swallow small items whole, and they hold large prey in their jaws, then rip it to shreds with their strong front claws.

www.google.com/books/edition/Wildlife_of_Virginia_and_Maryland_and_Wa/W7UxSPd2XMAC?hl=en&gbpv=1&dq=snapping+turtle+claws+prey&pg=PA403&printsec=frontcover

The forefeet and claws are used to tear larger prey into bite size pieces, and food is swallowed underwater.

www.google.com/books/edition/Amphibians_and_Reptiles_of_the_Great_Lak/hEc_DwAAQBAJ?hl=en&gbpv=1&dq=snapping+turtle+claws+prey&pg=PA177&printsec=frontcover

Do bears count as a clawed grappling predator? They're pretty inefficient and cruel and simply gnaw on their prey with no level of urgency since its target can't hurt it.

[Infinity Blade]

Jun 20, 2023 8:13:39 GMT 5 Bolushi said:

Jun 20, 2023 7:12:01 GMT 5 Infinity Blade said:

I find it ironic how out of the predators mentioned above, it's actually the pursuit & bite predators, particularly canids and hyaenids, that slash and disembowel their prey. Obviously they do it with their teeth, but the results are absolutely gruesome, and they do it with far, FAR more regularity than clawed grappling predators. So much so that wolves, African wild dogs, and spotted hyenas have been condemned as "cruel" for utilizing such a hunting method.

Back in the Campanian and Maastrichtian, I'm sure you would've been far more likely to see a tyrannosaurid spilling the guts of its prey with its teeth than a dromaeosaurid doing so with its claws (although, the dromaeosaurid still has a long jawline filled with ziphodont teeth, so it could still do the same with its own dentition).


This is the best alternative I could provide. Authors have written about snapping turtles biting and then ripping apart prey with their claws in the context of the wild.

www.google.com/books/edition/Wildlife_of_Virginia_and_Maryland_and_Wa/W7UxSPd2XMAC?hl=en&gbpv=1&dq=snapping+turtle+claws+prey&pg=PA403&printsec=frontcover

www.google.com/books/edition/Amphibians_and_Reptiles_of_the_Great_Lak/hEc_DwAAQBAJ?hl=en&gbpv=1&dq=snapping+turtle+claws+prey&pg=PA177&printsec=frontcover

Do bears count as a clawed grappling predator? They're pretty inefficient and cruel and simply gnaw on their prey with no level of urgency since its target can't hurt it.

They do. What you say has some truth to it, considering bears in general aren't specialized predators the way cats, wolves, etc. are. The body parts they attack on livestock in comparison to wolves, cougars, and coyotes is kind of telling.



open.alberta.ca/dataset/b5bee14e-1339-48b7-9388-b71bc6d378d1/resource/8fbe1c21-cb35-4485-8df8-439c8e83e7b7/download/ranchersguidetopredatorattacks-mar2018.pdf

[Shri devi]

I do think that most Eudromaeosaurs(Deinonychus being the prime example) were using their feet for grappling. That said, I think it's rather peculiar that their second ungual was so laterally compressed while being so hypertrophied, compared to the laterally compressed but relatively less hypertrophied second unguals of Cariamiformes, other Non-Eudromaeosaur Deinonychosaurs and basal Paravians or the hypertrophied but broad first and second unguals of Accipitrids. I assume that this would've had the effect of making the claws good for penetrating deeply but somewhat poor at resisting transverse and torsional forces like those incurred when hanging onto large struggling prey. Some fossils also show the keratin sheath being exceptionally long and coming to a very fine point, again good for penetration, bad for resisting forces. Plus, the fact that the second ungual was the only hypertrophied one means that it would have been taking the brunt of forces acting on the grasping foot while for a raptor, the load could be distributed between the four large robust unguals. Now, having grappling forelimbs compensates for this somewhat but idk how to quantify how much of an effect this would have, and the hands are some distance away from the feet. I also just think that if they were specialized for holding on and not letting go like Accipitrids, it'd just be beneficial to have broader second unguals, plus somewhat hypertrophied first unguals since those weren't involved in locomotion anyway (maybe something like Balaur).

I suspect that Eudromaeosaurs may have employed a more dynamic grappling style that involved disengaging and reengaging with the feet (maybe purposefully walking up the body of the prey to put their jaws in range of the throat or belly) as opposed to grabbing on and not letting go like Accipirtrids. This would lower the risk of claw breakage. Some features of the feet seem more suited for more rapid release than Accipitrids: 1) the second digit and its ungual are hyperextensible; 2) the second digit would've had a strong extensor system to keep it aloft, maybe even stronger than the flexors; 3) idk if they would've had ratcheting tendons to keep the toes flexed like in raptors and perching birds but even if they did, the comparatively smaller flexor tubercles implies that these would've been smaller and easier to release; 4) only the second digit ungual would have penetrated very deeply and there's no large opposing hallux. Extension of the leg could also be used to force the claw to retract since the leg extensors would've been much stronger than the digit flexors. A sharp ventral keep to the keratin sheath would've helped the claw cut its way out, not making big slashes or anything, just opening the wound a bit.

Anyways, so what does any of this have to do with the thread? Well, constant withdrawing and reengaging with the claws would've achieved a few things aside from just allowing the Eudromaeosaur to reposition itself and to keep its claws from breaking. For one, it would've been making more stabs, which means more trauma and chances of puncturing something vital. For another, it's often said that pulling a knife out is worse than keeping it in. An impaling instrument, if left in the wound, partly obstructs it and slows bleeding. Removing it opens the wound. Every time a Dromie retracted its claw, it would leave a deep open wound while Accipitrids plug the punctures that they make. So, even if Eudromaeosaurs weren't killing prey with claw slashes, it MAY be that they could have often flicted significant, potentially fatal trauma with the claws in the process of using them to grapple, perhaps more often than eagles do.

Interestingly, Dromaeosaurine Eudromaeosaurs that preserve the penultimate phalanx on the second digit (Achillobator, Dromaeosaurus, MAYBE the Bissekty giant?) show that this phalanx was rather stout in this clade compared to Saurornitholestines, (most) Velociraptorines, Deinonychus, etc. It's been suggested that this implies a reduced ungual like Adasaurus or Kuru and that Dromaeosaurines relied more on their robust jaws but 1) the one Dromaeosaurine with a preserved second ungual, Utahraptor, definitely did not have a reduced one and 2) unlike in Adasaurus and Kuru, the distal articular facet of phalanx II-2 in Dromaeosaurines don't appear reduced despite the stoutness of the bone. A shortened penultimate phalanx implies a reduced grasping capability (birds of prey elongate the penultimate phalanges) but improved leverage for flexion and extension of the claw. Could this imply that this clade was using their claws more for stabbing than grasping, maybe since their robust jaws could better engage prey without much grappling? Maybe the jaws could even aid the forelimbs in restraining prey so that they can be kicked fighting dinosaurs style?

Oh and ditto for Megaraptorans.

[Supercommunist]

Nov 20, 2024 17:16:33 GMT 5 Shri devi said:

I do think that most Eudromaeosaurs(Deinonychus being the prime example) were using their feet for grappling. That said, I think it's rather peculiar that their second ungual was so laterally compressed while being so hypertrophied, compared to the laterally compressed but relatively less hypertrophied second unguals of Cariamiformes, other Non-Eudromaeosaur Deinonychosaurs and basal Paravians or the hypertrophied but broad first and second unguals of Accipitrids. I assume that this would've had the effect of making the claws good for penetrating deeply but somewhat poor at resisting transverse and torsional forces like those incurred when hanging onto large struggling prey. Some fossils also show the keratin sheath being exceptionally long and coming to a very fine point, again good for penetration, bad for resisting forces. Plus, the fact that the second ungual was the only hypertrophied one means that it would have been taking the brunt of forces acting on the grasping foot while for a raptor, the load could be distributed between the four large robust unguals. Now, having grappling forelimbs compensates for this somewhat but idk how to quantify how much of an effect this would have, and the hands are some distance away from the feet. I also just think that if they were specialized for holding on and not letting go like Accipitrids, it'd just be beneficial to have broader second unguals, plus somewhat hypertrophied first unguals since those weren't involved in locomotion anyway (maybe something like Balaur).

I suspect that Eudromaeosaurs may have employed a more dynamic grappling style that involved disengaging and reengaging with the feet (maybe purposefully walking up the body of the prey to put their jaws in range of the throat or belly) as opposed to grabbing on and not letting go like Accipirtrids. This would lower the risk of claw breakage. Some features of the feet seem more suited for more rapid release than Accipitrids: 1) the second digit and its ungual are hyperextensible; 2) the second digit would've had a strong extensor system to keep it aloft, maybe even stronger than the flexors; 3) idk if they would've had ratcheting tendons to keep the toes flexed like in raptors and perching birds but even if they did, the comparatively smaller flexor tubercles implies that these would've been smaller and easier to release; 4) only the second digit ungual would have penetrated very deeply and there's no large opposing hallux. Extension of the leg could also be used to force the claw to retract since the leg extensors would've been much stronger than the digit flexors. A sharp ventral keep to the keratin sheath would've helped the claw cut its way out, not making big slashes or anything, just opening the wound a bit.

Anyways, so what does any of this have to do with the thread? Well, constant withdrawing and reengaging with the claws would've achieved a few things aside from just allowing the Eudromaeosaur to reposition itself and to keep its claws from breaking. For one, it would've been making more stabs, which means more trauma and chances of puncturing something vital. For another, it's often said that pulling a knife out is worse than keeping it in. An impaling instrument, if left in the wound, partly obstructs it and slows bleeding. Removing it opens the wound. Every time a Dromie retracted its claw, it would leave a deep open wound while Accipitrids plug the punctures that they make. So, even if Eudromaeosaurs weren't killing prey with claw slashes, it MAY be that they could have often flicted significant, potentially fatal trauma with the claws in the process of using them to grapple, perhaps more often than eagles do.

Interestingly, Dromaeosaurine Eudromaeosaurs that preserve the penultimate phalanx on the second digit (Achillobator, Dromaeosaurus, MAYBE the Bissekty giant?) show that this phalanx was rather stout in this clade compared to Saurornitholestines, (most) Velociraptorines, Deinonychus, etc. It's been suggested that this implies a reduced ungual like Adasaurus or Kuru and that Dromaeosaurines relied more on their robust jaws but 1) the one Dromaeosaurine with a preserved second ungual, Utahraptor, definitely did not have a reduced one and 2) unlike in Adasaurus and Kuru, the distal articular facet of phalanx II-2 in Dromaeosaurines don't appear reduced despite the stoutness of the bone. A shortened penultimate phalanx implies a reduced grasping capability (birds of prey elongate the penultimate phalanges) but improved leverage for flexion and extension of the claw. Could this imply that this clade was using their claws more for stabbing than grasping, maybe since their robust jaws could better engage prey without much grappling? Maybe the jaws could even aid the forelimbs in restraining prey so that they can be kicked fighting dinosaurs style?

Oh and ditto for Megaraptorans.

My main question is whether there are any animals that kill in this manner today. Keratin claws are substantially duller and more delicate than teeth so I feel that there is a large risk of them being broken if they are used to stab repeatedly.

[Shri devi]

Nov 21, 2024 12:27:21 GMT 5 Supercommunist said:

Nov 20, 2024 17:16:33 GMT 5 Shri devi said:

I do think that most Eudromaeosaurs(Deinonychus being the prime example) were using their feet for grappling. That said, I think it's rather peculiar that their second ungual was so laterally compressed while being so hypertrophied, compared to the laterally compressed but relatively less hypertrophied second unguals of Cariamiformes, other Non-Eudromaeosaur Deinonychosaurs and basal Paravians or the hypertrophied but broad first and second unguals of Accipitrids. I assume that this would've had the effect of making the claws good for penetrating deeply but somewhat poor at resisting transverse and torsional forces like those incurred when hanging onto large struggling prey. Some fossils also show the keratin sheath being exceptionally long and coming to a very fine point, again good for penetration, bad for resisting forces. Plus, the fact that the second ungual was the only hypertrophied one means that it would have been taking the brunt of forces acting on the grasping foot while for a raptor, the load could be distributed between the four large robust unguals. Now, having grappling forelimbs compensates for this somewhat but idk how to quantify how much of an effect this would have, and the hands are some distance away from the feet. I also just think that if they were specialized for holding on and not letting go like Accipitrids, it'd just be beneficial to have broader second unguals, plus somewhat hypertrophied first unguals since those weren't involved in locomotion anyway (maybe something like Balaur).

I suspect that Eudromaeosaurs may have employed a more dynamic grappling style that involved disengaging and reengaging with the feet (maybe purposefully walking up the body of the prey to put their jaws in range of the throat or belly) as opposed to grabbing on and not letting go like Accipirtrids. This would lower the risk of claw breakage. Some features of the feet seem more suited for more rapid release than Accipitrids: 1) the second digit and its ungual are hyperextensible; 2) the second digit would've had a strong extensor system to keep it aloft, maybe even stronger than the flexors; 3) idk if they would've had ratcheting tendons to keep the toes flexed like in raptors and perching birds but even if they did, the comparatively smaller flexor tubercles implies that these would've been smaller and easier to release; 4) only the second digit ungual would have penetrated very deeply and there's no large opposing hallux. Extension of the leg could also be used to force the claw to retract since the leg extensors would've been much stronger than the digit flexors. A sharp ventral keep to the keratin sheath would've helped the claw cut its way out, not making big slashes or anything, just opening the wound a bit.

Anyways, so what does any of this have to do with the thread? Well, constant withdrawing and reengaging with the claws would've achieved a few things aside from just allowing the Eudromaeosaur to reposition itself and to keep its claws from breaking. For one, it would've been making more stabs, which means more trauma and chances of puncturing something vital. For another, it's often said that pulling a knife out is worse than keeping it in. An impaling instrument, if left in the wound, partly obstructs it and slows bleeding. Removing it opens the wound. Every time a Dromie retracted its claw, it would leave a deep open wound while Accipitrids plug the punctures that they make. So, even if Eudromaeosaurs weren't killing prey with claw slashes, it MAY be that they could have often flicted significant, potentially fatal trauma with the claws in the process of using them to grapple, perhaps more often than eagles do.

Interestingly, Dromaeosaurine Eudromaeosaurs that preserve the penultimate phalanx on the second digit (Achillobator, Dromaeosaurus, MAYBE the Bissekty giant?) show that this phalanx was rather stout in this clade compared to Saurornitholestines, (most) Velociraptorines, Deinonychus, etc. It's been suggested that this implies a reduced ungual like Adasaurus or Kuru and that Dromaeosaurines relied more on their robust jaws but 1) the one Dromaeosaurine with a preserved second ungual, Utahraptor, definitely did not have a reduced one and 2) unlike in Adasaurus and Kuru, the distal articular facet of phalanx II-2 in Dromaeosaurines don't appear reduced despite the stoutness of the bone. A shortened penultimate phalanx implies a reduced grasping capability (birds of prey elongate the penultimate phalanges) but improved leverage for flexion and extension of the claw. Could this imply that this clade was using their claws more for stabbing than grasping, maybe since their robust jaws could better engage prey without much grappling? Maybe the jaws could even aid the forelimbs in restraining prey so that they can be kicked fighting dinosaurs style?

Oh and ditto for Megaraptorans.

My main question is whether there are any animals that kill in this manner today. Keratin claws are substantially duller and more delicate than teeth so I feel that there is a large risk of them being broken if they are used to stab repeatedly.

Well, to my recollection, accipitrids sometimes kill prey through trauma inflicted by the talons though they tend to eat things alive. Keratin is softer than enamel yes but it is worth noting that Dromaeosaurids would've had beta keratin claws which would've been harder than mammals' alpha keratin claws and there was a study that found that even tiger claws can leave traces on bone. We know Haast eagles punched holes in the pelvic bones of moas an order of magnitude larger than themselves with their talons. Not suggesting that Dromaeosaurs would've been inflicting bone damage on purpose per se (again, laterally compressed claw) but keratin isn't THAT weak. Plus, like I said, leaving the claws embedded in struggling prey exposes them to mediolateral forces to which they were most vulnerable while repeated stabbing would 1) let them avoid this and 2) mainly incur anteroposterior and dorsoventral forces to which the claws were much more suited for handling. 

There WAS another ecomorph of predators that killed by stabbing with long blades: sabertooths. Now again, enamel is harder than keratin and can hold an edge better, though a keratin claw could maintain the cutting edge, if it had one, through continuous growth. Plus, a broken off keratin claw tip can regrow which is another "advantage" over mammalian sabertooths. I think Accipitrids do sometimes survive and regrow broken talons. Dromaeosaurs would've been able to do the same especially with a sizeable set of jaws that they could make do with in the mean time. I'd also assume the leg muscles of a Dromaeosaur to be substantially stronger than the neck muscles of a Machairodont.

[Supercommunist]

Nov 21, 2024 14:42:18 GMT 5 Shri devi said:

Nov 21, 2024 12:27:21 GMT 5 Supercommunist said:

My main question is whether there are any animals that kill in this manner today. Keratin claws are substantially duller and more delicate than teeth so I feel that there is a large risk of them being broken if they are used to stab repeatedly.

Well, to my recollection, accipitrids sometimes kill prey through trauma inflicted by the talons though they tend to eat things alive. Keratin is softer than enamel yes but it is worth noting that Dromaeosaurids would've had beta keratin claws which would've been harder than mammals' alpha keratin claws and there was a study that found that even tiger claws can leave traces on bone. We know Haast eagles punched holes in the pelvic bones of moas an order of magnitude larger than themselves with their talons. Not suggesting that Dromaeosaurs would've been inflicting bone damage on purpose per se (again, laterally compressed claw) but keratin isn't THAT weak. Plus, like I said, leaving the claws embedded in struggling prey exposes them to mediolateral forces to which they were most vulnerable while repeated stabbing would 1) let them avoid this and 2) mainly incur anteroposterior and dorsoventral forces to which the claws were much more suited for handling. 

There WAS another ecomorph of predators that killed by stabbing with long blades: sabertooths. Now again, enamel is harder than keratin and can hold an edge better, though a keratin claw could maintain the cutting edge, if it had one, through continuous growth. Plus, a broken off keratin claw tip can regrow which is another "advantage" over mammalian sabertooths. I think Accipitrids do sometimes survive and regrow broken talons. Dromaeosaurs would've been able to do the same especially with a sizeable set of jaws that they could make do with in the mean time. I'd also assume the leg muscles of a Dromaeosaur to be substantially stronger than the neck muscles of a Machairodont.

Accipitrids don't usually thrust their talons in repeatedly though. They usually just grab and hold. Repeated stabs seem to be inherently more stressful on the claws and toes claw than an eagle-like grab and hold. Just as an example, its pretty unlikely someone would be able to break my finger if I grabbed there arm and they proceeded to shake me around. But if I keep jabbing them with my extended fingers I could easily hurt them. Humans might have more delicate phalanges than other animal's but toes tend to be rather thin.


Claws do grow back, but it does take awhile. In addition, unlike an eagle or a hawk, a dromeosaur like deinonychus is more reliant on terrestrial locomotion so a damaged toe would have a larger impact.

Lastly, dromeosaur sickle talons are heavily recurved which suggests that snagging was a primary function. There aren't animals I know of that have completely straight claws, but I feel that a talon designed for multiple thrusts would be shaped more like a cassowary's claw.


I suppose the closest analog would be animals with keratin horns, animals that are clearly able to thrust their horns multiple times, but then again those horns are usually substantially thicker than a claw would be.