Use of Point-and-Shoot Photography to Compare Regional Differences inCanis latrans(Coyote) Skull Size

Abstract

Increasing interest in digital resources for zoological study have resulted in the creation of several online collections of specimens with varying degrees of complexity and sophistication. We illustrate how an inexpensively created archive of digital photographs can be used to test hypotheses of general interest to evolutionary biologists. We used conventional and digital measurements from Canis latrans (Coyote) crania, to show that northeastern Coyote skulls are larger than skulls in our collection from all other areas. Furthermore, we reject Bergmann's rule by demonstrating that Coyote skulls from Texas are larger than skulls from Alaska and Washington. Measurements taken from calibrated digital photographs support conclusions drawn using conventional hands-on measurements from the same specimens. We employed simple point-and-shoot photography to make all images used. We have placed our images on a wiki platform without copyright restrictions; thus, they are available for use in any manner, and the digital archive can be expanded by others. We employed Bland—Altman plots to demonstrate an approach to image-quality control that can be employed to identify and replace images that could lead to erroneous measurements. We describe how digital archives shared in this manner could aggregate data from isolated specimens and small collections to make these otherwise obscure specimens available to the broader scientific community and the general public.