Zach Olson

Zachary H. Olson, Ph.D.

Associate Professor of Animal Behavior

School of Social and Behavioral Sciences


Decary Hall 335
Biddeford Campus
Eligible for Student Opportunities



Purdue University
Frostburg State University
South Dakota State University

Post-Doctoral Training

Post-Doctoral Training, Department of Forestry & Natural Resources
Purdue University (West Lafayette, Indiana)


Current research

Using non-invasive genetics to diagnose Northern bog lemming occurrence: Northern bog lemmings are a state threatened species in Maine. We know very little about their behavior, ecology, or even their distribution. My students and I are working in the field and in the lab to develop a molecular tool that will allow us to distinguish the threatened Northern bog lemming from its congener, the putatively more-common Southern bog lemming.  This project is the first step in improving our understanding of 1) where Northern bog lemmings are, 2) what they are doing, and 3) how we might better conserve them.  

Investigating grey seal food habits: Grey seals are in the process of an impressive comeback in numbers, and concerns are being raised that grey seals are more and more competing with commercial fisheries operations for desirable groundfishes like cod.  My colleague in the School of Marine Programs, Dr. Kathryn Ono, and I along with our students have developed and are using molecular tools to determine food habits of the now abundant grey seals.  

Scavengers and foraging risk: The world outside can be a scary place.  We know that most animals, if given the chance, will engage in foraging on carrion (i.e., dead animals). However, the decisions animals make, on a case-by-case basis, to engage or not to engage in foraging on carrion are still a mystery. My students and I are investigating foraging decisions made by scavengers when faced with a potentially free meal associated with carrion.     

Selected publications

McCosker, C., Z. H. Olson, and K. Ono. 2023. Multiple methods of diet analysis illuminate foraging ecology of the northwest Atlantic gray seal Halichoerus grypus. Canadian Journal of Zoology 102(2):182-194. [link]

Schutt, E., R. Francolini, N. Price, Z. H. Olson, and C. J. Byron. 2023. Supporting ecosystem services of habitat and biodiversity in temparate seaweed (Saccharina spp.) farms. Marine Environmental Research 191:106162. [link]

Hope, A. G., K. M. Headless, Z. H. Olson, and B. J. Wiens. 2023. Systematics, biogeography, and phylogenomics of northern bog lemmings (Cricetidae), cold-temperate rodents of conservation concern under global change. Systematics and Biodiversity 21:1. [link]

Olson, Z. H., C. Torlone, C. M. Russell, C. A. Wood, J. F. Welch, and K. M. Burkholder. 2022. Foraging risk in scavenging ecology: a study of scavenger behavior and patterns of bacterial growth. Basic and Applied Ecology 61:10-19. [link]

Danziger, A. M., Z. H. Olson, and M. Frederich. 2022. Limitations of eDNA analysis for Carcinus maenus abundance estimations. BMC Ecology and Evolution 22:14. 10.1186/s12862-022-01969-z

Wuerthner, V. P., S. J. A. Kimble, Z. H. Olson, N. G. Burgmeier, and R. N. Williams. 2021. High landscape-level gene flow in the red-backed salamander (Plethodon cinereus). Journal of North American Herpetology 2021(2):1-7.

Denny, K. N., Bilodeau, K. N., Dumont, C. A., and Z. H. Olson. 2021. Separating effects of spatial location and microhabitat density on perceived predation risk in small mammals. Acta Ethologica 24(1):1-7. [link]

Dufault, M., Z. H. Olson, D. Mellone, K. Flanders, and K. A. Ono. 2021. Flatfish may be underestimated in the diet of grey seals (Halichoerus grypus). Canadian Journal of Zoology 99(3):227-234.

Flanders, K. R, Z. H. Olson, and K. A. Ono. 2020. Utilizing next-generation sequencing to identify prey DNA in western North Atlantic grey seal Halichoerus grypus diet. Marine Ecology Progress Series 655:227-240.

McCosker, C., K. Flanders, K. Ono, M. Dufault*, D. Mellone*, and Z. H. Olson. 2020. Metabarcoding fecal DNA reveals extent of Halichoerus grypus (Gray seal) foraging on invertebrates and incidence of parasite exposure. Northeastern Naturalist 27(4):681-700.

Powers, K. D., D. N. Wiley, A. R. Robuck, Z. H. Olson, L. J. Welch, M. A. Thompson, and L. Kaufman. 2020. Spatiotemporal characterization of non-breeding great shearwaters Ardenna gravis within their wintering range. Marine Ornithology 48(2):215-229.

Webster, S. C., Z. H. Olson, and J. C. Beasley. 2019. Occupancy and abundance of free-roaming cats in a fragmented agricultural ecosystem. Wildlife Research 46(4):277-284.

Beasley, J. C., Z. H. Olson, T. L. DeVault, and N. Selva. 2019. Ecological functions of scavenging. Pages 125-157 in Olea, P. P., P. Mateo-Tomas, and J. A. Sanchez-Zapata, eds. Carrion Ecology and Management. Springer. Wildlife Research Monographs Volume 2.

Ono, K. A., C. M. Steinbeiser, A. B. Coco, M. J. Sheehan, A. J. Beck, M. N. Dufault, K. M. Gilbert, J. J. Antonez, and Z. H. Olson. 2019. Detecting spiny dogfish in grey seal diets. Conservation Genetics Resources 11:481-485.

Steinbeiser, C. M., C. A. Wawrzynowski, X. Ramos, and Z. H. Olson. 2018. Scavenging and the ecology of fear: Do animal carcasses create islands of risk on the landscape? Canadian Journal of Zoology 96:229-236.

Beatty, W. S., J. C. Beasley, Z. H. Olson, and O. E. Rhodes, Jr. 2016. Influence of habitat attributes on density of Virginia opossums in agricultural ecosystems. Canadian Journal of Zoology 94:411-419.

Kenison, E. K., Z. H. Olson, and R. N. Williams. 2016. A novel transport system for hellbender salamanders (Cryptobranchus alleganiensis). Herpetological Conservation and Biology 11:355-361.

DeVault, T. L., J. C. Beasley, Z. H. Olson, M. Moleón, J. A. Sánchez-Zapata, J. A. Donázar, and A. Margalida. 2016. Ecosystem services provided by avian scavengers. Pages 235-270 in Sekercioglu, C., Wenny, D. G., and Whelan, C. J., eds. Ecosystem Services Provided by Birds. University of Chicago Press, Chicago, Illinois.

Dharmarajan, G., J. C. Beasley, W. S. Beatty, Z. H. Olson, J. A. Fike, and O. E. Rhodes, Jr. 2016. Genetic co-structuring in host-parasite systems: empirical data from raccoons and raccoon ticks. Ecosphere 7(3):e01269

Olson, Z. H., J. C. Beasley, and O. E. Rhodes, Jr. 2016. Carcass type affects local scavenger guilds more than habitat connectivity. PLoS ONE 11(2):e0147798. [link to full text]

Olson, Z. H., B. J. MacGowan, M. T. Hamilton, A. F. Currylowe, and R. N. Williams. 2015. Survival of timber rattlesnakes: incorporating individual and ecological effects. Herpetologica 71:274-279.

Beasley, J. C., Z. H. Olson, and T. L. DeVault. Ecological role of vertebrate scavengers. 2015. Pages 107-128 in Carrion Ecology, Evolution, and their Application. Benbow, M. E., J. Tomberlin, and A. Tarone, Eds. CRC Press, Boca Raton, Florida, USA.

Hoverman, J. T., Z. H. Olson, S. LaGrange, J. Grant, and R. N. Williams. 2015. A guide to larval amphibian identification in the field and laboratory. Purdue University Coop. Ext. Service, W. Lafayette, IN. FNR-496.

Olson, Z. H., D. G. Whittaker, and O. E. Rhodes, Jr. 2013. Translocation history and genetic diversity in bighorn sheep. Journal of Wildlife Management 77:1553-1563.

Olson, Z. H., N. G. Burgmeier, P. A. Zollner, and R. N. Williams. 2013. Survival estimates for adult eastern hellbenders and their utility for conservation. Journal of Herpetology 47:71-74.

Beasley, J. C., Z. H. Olson, W. S. Beatty, G. Dharmarajan, and O. E. Rhodes, Jr. 2013. Effects of culling on mesopredator populations dynamics. PLoS ONE 8:e58982.

Olson, Z. H., J. T. Briggler, and R. N. Williams. 2012. An eDNA approach to detect eastern hellbenders (Cryptobranchus a.  alleganiensis) using samples of water. Wildlife Research 39:629-636.

Beasley, J. C., Z. H. Olson, and T. L. DeVault. 2012. Carrion cycling in food webs: comparisons among terrestrial and marine ecosystems. Oikos 121:1021-1026.

Olson, Z. H., D. G. Whittaker, and O. E Rhodes, Jr. 2012. Evaluation of experimental genetic management in reintroduced bighorn sheep. Ecology and Evolution 2:429-443.

Olson, Z. H., J. C. Beasley, T. L. DeVault, and O. E. Rhodes, Jr. 2012. Scavenging community response to the removal of a dominant scavenger. Oikos 121:77-84.

Beasley, J. C., Z. H. Olson, G. Dharmarajan, T. S. Eagan, II, and O. E. Rhodes, Jr. 2011. Spatio-temporal variation in the demographic attributes of a generalist mesopredator. Landscape Ecology 26:937-950.

Eagan, T. S., II, J. C. Beasley, Z. H. Olson, and O. E. Rhodes, Jr. 2011. Response of small-mammal populations to the removal of a generalist mesopredator in a fragmented, agricultural landscape. Canadian Journal of Zoology 89:724-731.

DeVault, T. L., Z. H. Olson, J. C. Beasley, and O. E. Rhodes, Jr. 2011. Mesopredators dominate competition for carrion in an agricultural landscape. Basic and Applied Ecology 12:268-274.

Page, L. K., J. C. Beasley, Z. H. Olson, T. J. Smyser, M. Downey, K. F. Kellner, S. E. McCord, T. S. Eagan, II, and O. E. Rhodes, Jr. 2011. Reducing Baylisascaris procyonis roundworm larvae in raccoon latrines. Emerging Infectious Diseases 17:90-93.

Research interests

My scholarship in animal behavior can be divided into two broad categories. My students and I conduct applied research that seeks to inform efforts to conserve wildlife and we conduct basic research investigating facets of foraging behavior including scavenging ecology.