Research Spotlight: July 2018

Digital Coyote; an online archive of skulls

Contributed by: Osrica Mclean and Declan McCabe

How can you provide an authentic opportunity for undergraduate students to study geographical variation without hauling them to major metropolitan museums and arranging access to valuable specimens?  This question started a slightly obsessive odyssey that began with a single coyote skull and now stands at 125 skulls….and counting.

We selected coyotes because they are broadly distributed, frequently hunted and trapped, and therefore readily available.  Populations are thriving and there is little concern that our modest purchases of skulls might negatively affect populations.  Late night EBay and Etsy searches, emails to pest control companies, taxidermists, and hunting and trapping associations yielded the necessary specimens to build a serviceable teaching collection.

With about 25 skulls our students could already detect size differences between northeastern and western skulls.  Bergmann’s Rule seemed like the next logical question to approach and so we started building some latitudinal diversity into our collection of western coyote skulls extending from Texas to Alaska.  

Bergmann’s rule proved elusive; absence of pattern is less exciting for students; so we enlarged the collection.  Eventually patterns became detectable for students persistent enough to measure enough skulls.  Interestingly, the patterns ran counter to the predictions of Bergmann’s rule.  The “Everything is bigger in Texas” rule was, however, strongly supported.

We were lucky enough to have a budget for this project for several years, but many schools are less fortunate and so we considered how we might provide broader access to the collection.  An online museum of calibrated images seemed like a logical next step and so ‘Digital Coyote’ was born.

Image 1. Digital Coyote Museum; (McCabe and Vu 2014;

We shared the images without restriction on Wikimedia Commons and created pages with linked and cataloged images on Wikieducator.  Our ‘museum’ currently includes 168 skulls; 120 of which are coyotes.  Each skull page includes left and right lateral plus dorsal and ventral views of a particular skull.  Location information is typically state and sometimes county of origin.

We presented the project at the 2013 Association for Biology Laboratory Education conference in Calgary and published a lesson plan based on the collection in the proceedings.  Although we had confirmed the accuracy of each image at the time of upload, some teachers were concerned about the accuracy of our approach and therefore the validity and utility of the online resource.

To address the accuracy concerns and because we realized that ours was likely the most substantial collection of this nature outside of the major museums we decided to turn the project into a research publication.

Starting as a first year undergraduate student, Catherine Vu had systematically improved the accuracy of our photography while building the online collection.  In her junior year, she enlarged the posted collection and was joined by Devan Piniewski in their senior years at Saint Michael's College to focus on measurement using traditional methods and measurements form photographs.  The resulting paper was submitted shortly after the pair graduated.

As is typically the case, our reviewers had invaluable suggestions, recommendations, and also pointed out two potentially fatal flaws in our work: 1. We had measured greatest length of the skulls which is not precisely homologous from skull to skull; and 2. We had no idea of the ages of any of the animals and therefore could not account for potential age biases across the geographical areas being compared.

Osrica Mclean rose to the occasion to address both concerns.  She re-measured every skull using condylobasal length and then used basicranial suture closure to place the skulls into 4 age categories.  After Osrica successfully addressed all of the reviewers’ concerns, the paper was accepted for publication in Northeastern Naturalist the day before she graduated.

In closing, we’d like to add that resources like the physical collection we built, are always at risk.  At some point professors retire and because educational institutions must change to meet the needs of their student market, it is rare that newly hired professors will have the skills and interests of the professor they replace.  What then is to become of a bulky skull collection?  Would it be accepted by a larger museum? Or disposed of?  Digital collections offer one way to at least preserve images of collected skulls and make them freely available to educators and researchers.

We are by no means finished with our research on coyote skulls and look forward to the next eager undergraduate student interested in improving their skill set by addressing interesting questions using coyote skulls, digital or physical!