IUCN / SSC Cat Specialist Group - Digital Cat Library |
|
||||||||||
|
||||||||||
|
|
| Chamoli, U. | |
| Biomechanics of felid skulls: a comparative study using finite element approach | |
| 2011 Full Book | |
Shape and scale-related effects on biomechanical construct of organisms depend strongly on the properties and distribution of materials of which they are built, with an inherent requirement for avoiding failure over the entire lifetime. The cat family (Felidae) has been considered morphologically and behaviourally conservative, and hence an appropriate focus for investigations into the role of allometry. Here I apply three-dimensional (3D) finite element analysis (FEA) to models representing the skulls of seven extant felid species in order to (1) more fully assess their biomechanical performance; and (2) to predict allometric trends regarding overall geometry and relative distributions of cortical and cancellous bone. Results derived from incorporating material properties distribution for cortical and cancellous bone in the finite element models (FEMs) largely support the contention that mechanical behaviour in the felid skull is conservative across species. A negative allometric trend between cortical bone volume and total skull bone volume, and positive allometry between total skull bone volume and skull surface area were also observed. Further mathematical modelling using beam mechanics suggests that these allometric trends reflect a need for larger species to respond to physical challenges associated with increased size, and, that changes in skull shape, bone composition, or a combination of both, may be required to accommodate these challenges. I conclude that as felids become larger, overall skull bone volume relative to surface area increases by adding less dense and more compliant cancellous bone. This brings an overall saving in mass and a reduced burden on metabolism to produce biologically expensive cortical bone, without compromising much on the overall stiffness. In a further study, I constructed 3D FEMs of two extinct sabretooth predators (_Smilodon fatalis _and _Thylacosmilus atrox_) to investigate functional convergence. Relative to the conical-toothed _Panthera pardus_, predicted jaw muscle driven bite forces in both were low, but their skulls appeared well-adapted to resist forces generated by cervical muscles. Although findings for _S. fatalis _are consistent with an extension of 'normal' biting behaviour, estimated jaw adductor driven bite forces for _T. atrox _considered with evidence for a major translational component, suggest that it was more specialised. |
|
 |
PDF files are only accessible to Friends of the Cat Group. Joining Friends of the Cat Group gives you unlimited access and downloads in the Cat SG Library for one year, and allows you to receive our newsletter Cat News (2 regular issues per year plus special issues). More information how to join here |
(c) IUCN/SSC Cat Specialist Group ( IUCN - The World Conservation Union) |