Fig. 2. Examples of skulls, strain gage locations, and measurements. (A) Skull of a piglet of the age used in the present study; condylobasal length approximately 100 mm. A strip gage, consisting of three parallel anterior-posteriorly oriented single-element strain gages, is illustrated on the zygomatic bone (Z), and a stacked rosette gage is shown on the squamosal bone (Sq). (B) Skull of a juvenile animal, a sibling of one used in the previous study (Herring et al., 1996); condylobasal length 200 mm. (C) Skull from a young adult (dentition complete except for third molars); condylobasal length approximately 270 mm. Note the progressive deepening and curving of the zygomatic arch with increasing age. (D) Ventral view of a disarticulated left squamosal bone, showing the articular eminence (AE) with the medial shelf (arrow) that sometimes continued to the level of the gage site, where squamosal thickness (SqTh) was measured. (E) Bone dimensions. Zygomatic body length (ZL) was measured from the most posterior part of the maxillary-zygomatic suture to the corner of the zygomatic-squamosal suture. Squamosal bone length (SqL) was measured from the zygomatic-squamosal suture corner to the posterior extent of the suture. Bone height (ZH and SqH) was measured vertically (relative to the occlusal plane) at the gage sites. Medial-lateral bone thickness (at the stars) was also measured at the gage sites. (F) Method for estimating ventral curvature. A straightedge was laid across the most ventral parts of the sutures (ZX and SqX). From these lines, the heights of the maximum perpendiculars (ZY and SqY) were measured. Curvature was estimated as ZY/ZX and SqY/SqX.