Lab Members


Doctoral Students

Dylan Maag

received my B.S. in Fisheries and Wildlife with a focus on Conservation Biology from the University of Nebraska-Lincoln and my M.S. in Biology at Missouri State University.  My thesis research was focused on the spatial ecology and habitat selection of the pygmy rattlesnake, Sistrurus miliarius.  Currently, my doctoral research focuses on the behavioral and ecological mechanisms underlying differential fitness and their relationship to an individual’s ancestry. To study this, I am using a rattlesnake hybrid system between Crotalus viridis and C. scutulatus. However, I still hold interests in in other areas of herpetology including, conservation, demography, and the evolution and practical application of sensing organs.  Email:


Craig Fischer

I have long been interested in myriad aspects of ecology, using my bachelor's in Biological Sciences from Marquette University and bio tech positions in public lands to ask pointed questions about effects of climate change, habitat alteration, and recreation on ecology of public lands. Four years working in the Colorado Desert have given me ample opportunity to develop questions regarding the ecology of this remarkable region. My research focuses on how natural and anthropogenic landscape factors may affect genetic diversity of flat-tailed horned lizards (Phrynosoma mcalli) within an off-road focused recreation environment. Email:

RH Copperhead

Ryan Hanscom

received my B.S. in Biology from Framingham State University and my M.S. in Biology from Tennessee Technological University. During my B.S., my research focused on population biology of freshwater turtles on a barrier island and during my M.S., I examined how ecology and geography influence the species diversification of snapping shrimps. Generally, I am interested in the ecology, evolution, and conservation of herpetofauna. My current research uses a naturally occurring thermal cline to examine how increases in environmental temperature affect predator-prey interactions between prairie rattlesnakes (Crotalus viridis) and Ord’s kangaroo rats (Dipodomys ordii). Email:

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Ana Gomez Ramirez

I am currently co-advised between Dr. Clark and Dr. Jeremy Long in the Ecology Program Area. I received my B.S. in Biology from San Diego State University, where I developed an interest in island ecology, and the relationships between animal behavior and nutrient cycling across ecosystems, particularly as they relate to marine subsidies of island ecosystems. I am currently exploring the terrestrial community of a nearby offshore island chain (Islas Coronados in Mexico), and my research will focus on understanding the linkages between the terristrial community and the surrounding oceanic ecosystem. Email:

Masters Students


Roman Nava

My main interests are animal behavior and conservation, and here I am interested in how species change their behaviors as a result of natural and anthropogenic fragmentation, and seeing if there is any convergence (or difference!) in how species respond to fragmentation across fragments created by urbanization or islandization. I look at morphological changes coupled with personality assays, combining two sets of data to draw insights from. My current project tests these ideas on a handful of squamates at a few sites around San Diego County and Coronado Sur of Baja California, Mexico. As urbanization rapidly increases, it is important to know if species are responding to fragmentation caused by humans in a similar way to fragmentation caused by natural forces over thousands of years. 


Jordyn Mulder

I received my B.S. in Wildlife Biology with an emphasis in management and conservation at Humboldt State University in 2013. Since then, I have pursued my passion for herpetofauna.  My main topics of interest are animal behavior, conservation, and human and wildlife interaction. My current research is in San Diego studying local lizard populations and using skeletochronology to determine morphological changes over time due to isolation and climate change. Email:


Nathaniel Redetzke

I am working as a wildlife officer at Camp Pendleton while obtaining my MS degree in the Clark lab.  Part of my duties involve translocating venomous snakes that show up near houses or active training operations. For my thesis work, I am studying how individual variation in snake temperament mediates their response to translocation. This involves using a series of behavioral assays to characterize snake temperatment, and then using radio telemetry to also quantify the spatial ecology of translocated and non-translocated snakes. Email: 

Nathan Smith


I'm a lifelong Herpetologist. I graduated Cal State San Marcos in Fall of 2015 with a BS in Biology and Ecology concentration. I've been seriously pursuing and recording reptiles and amphibians in the San Diego region since 2007 with over 2,000 records in the database. I am currently a field tech with USGS at the Western Ecological Research Station, San Diego working on projects focused on endangered and threatened species. I am trying to expand my depth of knowledge about the species present in San Diego beyond the herptofauna which I have dedicated most of my time to studying. Scorpions are one of my other primary interests. Email:

Jessica Hill

I received my B.S. in Biology from the College of William and Mary in Williamsburg, VA, where I studied the anti-inflammatory properties of host-defense peptides. However, I found that my passion did not lie in biochemistry but in the understanding and applications of ecology and conservation. Specifically, my interests lie in the spatial ecology and overall movement of animals as well as anthropogenic impacts. My current research focuses on the potential effects of climate change on predator-prey interactions between prairie rattlesnakes (Crotalus viridis) and Ord’s kangaroo rats (Dipodomys ordii). I aim to examine this through a combination of ecological niche modeling, accelerometry, and telemetry work.  Email:

Graduate Student Alumni

Matthew Barbour, MS 2012, Investigating the function of California ground squirrel (Otospermophilus beecheyi) displays towards northern Pacific rattlesnakes (Crotalus oreganus)  

Frank Santana, MS 2013, Mountain yellow legged frog (Rana muscosa) conservation: multiple approaches

Shannon Hoss, PhD 2013, Maternal attendance of young in cottonmouths (Agkistrodon piscivorus): Adaptive value and hormonal mechanisms

Laura Kabes, MS 2014, The use of chemical cues by granite night lizards (Xantusia henshawi) to evaluate potential predation risk

Bree Putman, PhD 2015, The function and ontogeny of antipredator responses: the influence of snakes on ground squirrel behavior and physiology 

Tara Luckau, MS 2015, Comparative conservation genetics of two sympatric lizard species across multiple landscapes in San Diego County

JP Montagne, MS 2015, The effect of personality on movement and survival following translocation of California ground squirrels (Otospermophilus beecheyi)

Kelly Lion, MS 2016, A comparative study of genetic patterns in two closely related and sympatric Peromyscus species

Stephen Rice, PhD 2017, Conservation genetic assessment of the Island Night Lizard, Xantusia riversiana, under contemporary and future environmental conditions

Hannes Schraft, PhD 2019, Behavioral and ecological implications of infrared sensing in rattlesnakes

Kelly Robinson, MS 2019, Biochemical warfare: coevolution of venom and venom resistance among rattlesnakes (Crotalus oreganus helleri and C. ruber) and mammal prey (Otospermophilus beecheyi and Neotoma bryanti

Malachi Whitford, PhD 2020, Determinants of predation success: a holistic examination of the predator-prey interactions between rattlesnakes and kangaroo rats

Grace Freymiller, PhD 2021, Factors that influence the performance of complex behaviors in a terrestrial vertebrate: variability in the kangaroo rat evasive leap

Last Updated:  December 2021