Comparing Cats: A Discussion of Similarities & Differences

[Pckts]

Bite Force:
 
Intro:
Bite force is one indicator of the functional state of the masticatory system that results from the action of jaw elevator muscles modified by the craniomandibular biomechanics.1 Determination of individual bite force level has been widely used in dentistry, mainly to understand the mechanics of mastication for evaluation of the therapeutic effects of prosthetic devices and to provide reference values for studies on the biomechanics of prosthetic devices.2 In addition, bite force has been considered important in the diagnosis of the disturbances of the stomatognathic system.3
The bite force measurements can be made directly by using a suitable transducer that has been placed between a pair of teeth. This direct method of force assessment appears to be a convenient way of assessing the submaximal force. An alternative method is indirect evaluation of the bite force by employing the other physiologic variables known to be functionally related to the force production.4 Electromyographic activity of the surface elevator muscles of the mandible can be picked up from the cutaneous projection of the muscular belly.5 In this way, obtained data give an idea for the bite force. The results of some investigations showed a linear relationship between electromyographic activity potentials and direct bite force measurements, especially at a submaximal level.4
Several factors influence the direct measurements of the bite force. Thus, different investigators have found a wide range of maximum bite force values. The great variation in bite force values depends on many factors related to the anatomical and physiologic characteristics of the subjects. Apart from these factors, accuracy and precision of the bite force levels are affected by the mechanical characteristics of the bite force recording system.6
In this review, we emphasized important factors that affect bite force measurements, such as cranio-facial morphology, age, gender, periodontal support of teeth, signs and symptoms of temporomandibular disorders and pain, and dental status. In addition to these biological factors, mechanical determinants including different recording devices, position of recording devices in dental arch, unilateral or bilateral measurements, using acrylic splints and opening wide of mouth were reviewed.


Cranio-facial morphology
Maximum bite force varies with skeletal measures of the cranio-facial morphology that include the ratio between anterior and posterior facial height, mandibular inclination and gonial angle. It has been explained that bite force reflects the geometry of lever system of mandible. When the ramus is more vertical and the gonial angle acute, elevator muscles exhibit greater mechanical advantage.1,7–10
Pereira et al11 have found a negative correlation between bite force and mandibular inclination. This result is consistent with the other studies in which the long-faced type of the cranio-facial morphology has been associated with smaller values of the bite force.8,10 The same researchers have also suggested a significant correlation between bite force and muscle thicknesses and between masseter-temporal muscle thickness and facial morphology.11 In this respect, Farella et al12 have stated that masseter muscles are thicker in short-faced subjects than in normal or long-faced subjects. From the results of these studies, it seems that short-faced people may exhibit stronger bite force.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2853825/




"Results
Analyses of Linear Variables
Males and Females are statistically distinct across each of the linear variables (I-XVII), as we hypothesized (H2); males are substantially larger than females in all linear measures (Table 4). However, the sexes do not differ by either of the shape ratios. Those ratios clearly separate lions from tigers as lions have significantly longer rostra and narrower biangular widths – thus supporting H1 as well. Although the upper carnassial (P4) and premolar-molar rows in lions are only slightly longer than those of tigers (35.57 mm vs. 33.79 mm and 68.25 vs. 63.12 respectively), these differences were also highly significant. All of the statistically significant differences including these tooth lengths along with basal skull length (II), two different metrics related to jaw length (V, and X), and the aforementioned mentioned rostral lengths (I and XIV), all relate, essentially, to the lion’s overall longer muzzle while the tiger has a significantly wider rostrum (XV). (Table 4).


"The first principal component is driven most substantially by the anterior-most points relative to the position of the points that lie most close to the midline of the skull in the lateral view – i.e., the position of the zygomatics and the post-orbital processes (Fig. 6). Given that this axis divides the population by species, it is not surprising that the variables that emerge describe the relatively longer muzzle of lions relative to tigers. What is somewhat contrary to what we would have predicted both the anterior-most and posterior-most points show an anterior shift from the tiger morphospace (represented in Fig. 6– by the dot) to the lion morphospace (represented by the end of the line emerging from the dot). Thus the longer rostra found in lions is driven not by an elongation of the anterior portion of the skull, but by the relatively posterior position of the zygomatics and orbits. In other words, according to this analysis, tigers do not have relatively shorter snouts, but relatively rostral eyes and cheeks"

http://journals.plos.org/plosone/article...ne.0113437



Differences across species were evident upon examination of the wireframe renderings of the specimens in Morphologika. One difference is a shortened rostrum in the tiger specimens relative to the lion specimens, which is consistent with descriptions of tigers (Sunquist and Sunquist 2002). This is a possible topic for future research. Mandibular angles also varied across the species, as tigers exhibited wider bi-coronal breadths and lions exhibited wider bi-angular breadth. The results of the PCA output are encouraging, demonstrating the ability of statistical analysis to account for observable qualitative differences across specimens. Variation of skull width and in biangular-anterior mandibular angle, or dome shape was observed differences across captivity status. Wild specimens were found to have more robust domes, than captive (Figure 1). Relatedly, captive specimens had greater skull widths relative to length than wild.
http://caravel.sc.edu/2014/12/the-crania...ve-felids/



Relative to weight, it’s the jaguar. Recent research by Adam Hartstone-Rose and colleagues at the University of South Carolina, who compared the bite forces of nine different cat species, reveals that jaguars have three-quarters the bite force of tigers.
However, given that jaguars are considerably smaller (the body mass of the individual in the study was only half that of the tiger), relatively speaking their bite is stronger.
“If you had to choose, you’d want to be bitten by a jaguar, not a lion or a tiger. But pound for pound, jaguars pack a stronger punch,” says Adam. “The strength of the jaguar’s bite is due to the arrangement of its jaw muscles, which, relative to weight, are slightly stronger than those of other cats. In addition – also relative to weight – its jaws are slightly shorter, which increases the leverage for biting.”
http://www.discoverwildlife.com/animals/...ngest-bite




From Bite club: comparative bite force in big biting mammals and the prediction of predatory behaviour in fossil taxa (from now I'm going to give paper names instead of just the in text citations to help folks locate the works easier) has the BFQs as follows:
Jaguar: 142 (unadjusted), 137 (allometry adjusted)
Leopard: 100 (unadjusted), 94 (allometry adjusted)
Tiger: 140 (unadjusted), 127 (allometry adjusted)
Cougar: 118 (unadjusted), 108 (allometry adjusted)
Lion: 118 (unadjusted), 112 (allometry adjusted)
Cheetah: 110 (adjusted), 119 (allometry adjusted)

To find a correlation with skull characteristics, here are the zygomatic width/basal length ratios of the cats (the greater the number the proportionately wider the skull):
Jaguar: 0.837
Leopard: 0.723
Tiger: 0.788
Cougar: 0.77
Lion: 0.743
Cheetah: 0.772


http://web.archive.org/web/2013082523132...r/wroe.pdf Reply