Biologists have long commented on how the vertebrate skeleton appears to be designed in accordance with engineering principles. Bones and their associated soft tissues are adapted to transmit, resist, and take advantage of the many forces the skeleton experiences during normal function. How bones respond to forces, that is, how they are stressed and strained, is therefore linked to their function. A great deal of functional information can be gained from examining how a skeleton responds to stresses and strains; yet paleontologists are limited because fossil bones are petrified (and thus have different properties than biomaterials in living animals), and skulls in particular are complex shapes not applicable to straightforward mathematical analysis. Recently, however, biologists and paleontologists have begun to borrow from the sophisticated design toolkit of engineers in order to examine skeletal construction.