Smilodon,The Overpowered True King of the Big Cats !

[kevin]

If there's one animal that genuinely deserved to be king of the big cats, it's the infamous Sabertooth Cat and certainly not the lion,tiger,or jaguar. This thread is dedicated to exploring the amazing strength of this extinct animal and proving how it was among the most powerfully built terrestrial mammalian carnivores on a pound for pound basis !

[kevin]

Let's start with this list of some very important strength indicators :

Brachial Index - BI:[/u]
This measures radius length/humerus length. Lower scores in this ratio indicate greater forelimb muscle mechanical advantage and results in stronger muscles all else being equal. Arboreal felids, which climb often, tend to score high which also likely results in them being able to grapple well all else being equal.
HRI - Humerus Robusticity Index:[/u]
It is humerus mediolateral diameter at mid-shaft/humerus length. Robust forelimb bones protect the animal from violent stresses during grappling.
Humeral - Epicondylar Index - HEI:[/u]
The HEI index measures the relative size of wrist stabilizing muscles and well as several grasping muscles in area which facilitate prey grasping. These muscles also likely help stability, pushing, and agility when legs are on ground.
PAW - Proximal Paw Width:[/u]
This is a measurement of paw width on forelimbs and gives us an idea of how well-paws are designed to hold prey. In addition, relatively wider paws likely increase stability while feet are on ground.
Olecranon Index - OI:[/u]
This metrics estimates tricep muscle strength. High values indicate greater ability to push with arms all else being equal. This helps a grappling cat hold prey and also helps a canid push and knock down an opponent. In addition, higher values may indicate greater stability and ability to change direction in a fight.
RRI - Radial Robusticity Index:[/u]
This measures radius mediolateral diameter at midshaft divided by radius length. As mentioned above for humerus robusticity, a robust radius resists stresses on bones during fights and increases resistance to bites to the forelimb.


If we compare smilodon to pantherine cats, you'll notice that the former exceeded the latter in all strength indicators :



www.researchgate.net/publication/261974255_Morphological_convergence_of_the_prey-killing_arsenal_of_sabertooth_predators

Notice that smilodon outscored some other prehistoric cats such as homotherium and dinictis felina

[kevin]

Here are some more indicators :


Kcc :[/u]
values closer to 100% signify relatively thinner cortical bone and values closer to 0% signify relatively thicker cortical bone.
Kml :[/u]
values closer to 100% signify relatively thinner cortical bone and values closer to 0% signify relatively thicker cortical bone.
CA/Length :[/u]
This measure is used to estimate aspects of long bone strength in axial compression.
Lx/length :[/u]
This measure is used to estimate aspects of long bone strength in bending about mediolateral plane.
Ly/length :[/u]
This measure is used to estimate aspects of long bone strength in bending about craniocaudal plane.
J/2/length :[/u]
This measure is used to estimate aspects of long bone strength in average rigidity in non-axial loading.

Then again, smilodon scored better than pantherine cats in all bone robusticity ratios. According to the study itself, there are significant differences in smilodon's favor :

Amazingly, Smilodon Fatalis scored the best in terms of forelimb strength among felines, with only the American Panthera Atrox barely coming close :


journals.plos.org/plosone/article?id=10.1371/journal.pone.0011412

[kevin]

Another study on locomotion has found out that smilodon had limb bones similar to those of bears :

www.researchgate.net/publication/229600388_Locomotor_behaviour_in_Plio-Pleistocene_sabre-tooth_cats_A_biomechanical_analysis


The extinct sabertooth cat was pretty much a cat in a bear's body.

[kevin]

A more recent study supported the above conclusion :

pubmed.ncbi.nlm.nih.gov/18313908/

[kevin]

Here Is a comparison between smilodon species,bear species and pantherine cat species:

Humeral Circumference Index:[/u]
Smilodon Populator : 40,13%-n=4
Smilodon fatalis : 33,7%-n=7
Smilodon gracilis : 33%-n=4
Kodiak bear : 35,7%-n=2
Cave bear : 34,4%-n=6
Arctodus simus : 31,8%-n=4
Polar bear : 32,27%-n=6
Non-kodiak Brown bear: 32%-n=4
Brown bear( Kodiak and non Kodiak) : 33,23%-n=6
Tiger : 30,3%-n=19
Lion : 31,8%-n=17
Jaguar : 32,2%-n=8
Leopard : 29%-n=16
Snow leopard : 29,7%-n=3
Femoral Circumference Index :[/u]
Smilodon Populator : 32,4%-n=2
Smilodon fatalis : 28,8%-n=7
Smilodon gracilis : 26,2%-n=1
Kodiak bear : 26,6%-n=2
Cave bear : 26,38%-n=7
Arctodus simus : 26,24%-n=3
Polar bear : 24,14%-n=6
Non-kodiak brown bear : 22,77%-n=6
Brown bear (Kodiak and non-kodiak) : 23,72%-n=8
Tiger : 25,2%-n=19
lion : 27,1%-n=17
Jaguar : 26,3%-n=8
Leopard : 24,6%-n=16
Snow leopard : 25,78%-n=3



Overall :[/b][/u]

Humeral Circumference Index :[/u]
Smilodon : 35,22%-n=15
Ursid : 33%-n=22
Pantherine : 30,58%-n=63
Femoral Circumference Index :[/u]
Smilodon : 29,26%-n=10
Ursid : 24,91%-n=24
Pantherine : 25,72%-n=63


References :[/u]


docs.google.com/spreadsheets/u/0/d/1eKb1sGNIAp1K5Fy4fX1EDn_1_IX1t9YkUqYao97m5cA/htmlview#



www.semanticscholar.org/paper/Osteology-and-ecology-of-Megantereon-cultridens-a-%E2%80%93-Christiansen-Adolfssen/f5dd2b7f596ef6b84aff81281e97e6f7f75422a6




pubmed.ncbi.nlm.nih.gov/16235255/



The above comparaison did support the notion that smilodon was bear-like in its structure and the above results suggest smilodon had relatively more stout limbs than pantherines and even bears !

[kevin]

Unlike the lion and tiger, no smilodon individual scored below the regression line. Not only that, but even the most robust lion barely comes close to the Most gracile smilodon as well. As for the the two most robust tigers, they too got outmatched by more than five Sabertooth cats :



publikationen.uni-tuebingen.de/xmlui/handle/10900/48480

[kevin]

The jaguar is generally considered,pound per pound,the strongest pantherine cat of the modern world. Yet even such imposing force of nature looked like a twig compared to smilodon fatalis especially when comparing their respective humeri from a mediolateral standpoint :

[kevin]

A study has the following to say :

Not only that, but smilodon populator was even more robust than panthera atrox according to this graph :


www.researchgate.net/publication/227999071_A_biomechanical_constraint_on_body_mass_in_terrestrial_mammalian_predators

[kevin]

Sabertooth cat species had relatively wider distal ends, more Powerfully built medial epicondyles and overall greater muscle attachements of the humerus than pantherine cats, including lions,tigers,and Jaguars :

academic.oup.com/zoolinnean/article/151/4/833/2607398

[kevin]

Smilodon Populator vs Siberian Tiger :

pubmed.ncbi.nlm.nih.gov/16235255/

When we divide the shaft circumference by humerus length, we get 39,24% for Populator and 27,88% for the tiger. This obviously goes to show that the Sabertooth has a proportionally far more massively built shaft. Not only this, but the Sabertooth owns significantly wider ends as well.

[kevin]

Jul 5, 2023 11:27:25 GMT kevin said:

Smilodon Populator vs Siberian Tiger :

pubmed.ncbi.nlm.nih.gov/16235255/

When we divide the shaft circumference by humerus length, we get 39,24% for Populator and 27,88% for the tiger. This obviously goes to show that the Sabertooth has a proportionally far more massively built shaft. Not only this, but the Sabertooth owns significantly wider ends as well.

This is how ngandong tiger humeri compare to the exact same amur tiger Humerus :

It would appear that the gap between their respective humeri isn't as large as the one between the Siberian Tiger and Smilodon Populator so it would appear that the Sabertooth was more powerful than the prehistoric tiger as well.

[kevin]

Tigers and modern cats in general don't even compare to Smilodon fatalis :


journals.plos.org/plosone/article?id=10.1371/journal.pone.0183175

[kevin]

pubmed.ncbi.nlm.nih.gov/16235255/

[kevin]

How would Smilodon fatalis and Smilodon Populator fit in the following graph ?



When we divide ML humerus diameter by humerus length, we get 12,71% for Smilodon fatalis as per the latest dataset :
www.researchgate.net/publication/230843015_Postcranial_morphology_and_the_locomotor_habits_of_living_and_extinct_carnivores
And we get 11,4% for Smilodon Populator as per this study :
pubmed.ncbi.nlm.nih.gov/16235255/

According to these numbers, we conclude that both Sabertooth species outscored a large number of felid,canid,hyeanid,mustelid,and Ursid species with fatalis being at the very top alongside roman bulldogs and Populator being a worthy rival for sloth bears in relative humeral robusticity. Credit to Hardcastle for the graph.