"Grapple and slash" predators are not (really) a thing
Jun 1, 2023 5:53:11 GMT 5
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Post by Infinity Blade on Jun 1, 2023 5:53:11 GMT 5
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:
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[/url]). 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).
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.
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.
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[/url]). 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.