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San Diego State University

Faculty-Student Mentoring Program

Rulon Clark, Ph.D.
Associate Professor of Biology

Clark in the field with SDSU undergrad
Mariana Perez taking data on a rosy boa.


My primary role as a faculty mentor is to show students that a career as a research scientist is exciting and enjoyable. There are incredible opportunities for research in the life sciences, but many undergraduates are often intimidated by the prospect of conducting research. However, once students are exposed to the research process, they often realize that not only can they actually begin undertaking scientific investigation, but also that doing so is a very rewarding endeavor. In addition to getting students excited about a career as a scientist, research experience helps students begin the transition from being a knowledge consumer to a knowledge producer. Students who plan on a career in scientific research will usually pursue graduate degrees. As graduate students, they will need to be able to work independently, developing their own hypotheses, designing their own experiments, and thinking critically about scientific literature. This is a very challenging transition. Research experience outside of regular coursework will not only help students develop as independent thinkers more rapidly, but will also aid them greatly when applying to graduate school. Most professors only accept graduate students that have already demonstrated a capacity for independent research as undergraduates. However, the benefits of participating in independent research as an undergraduate extend beyond those students in an academic career track. The skills learned while performing research, including critical thinking, problem solving, teamwork, and written and oral communication skills, are indispensible to any career.

My laboratory studies animal behavior, and how the behavior of individuals affects population processes and community dynamics. We are currently initiating a wide range of research projects, including studies of predator-prey interactions, social behavior, mating behavior, conservation ecology, and molecular ecology. We use a combination of field and laboratory studies. We work on a diverse array of species, but the majority of our work is conducted with reptiles and amphibians. Almost all of our projects involve observational and experimental approaches, and often require a fairly large team of researchers to monitor and record the behavior of both free-living animals, and animals that are part of our captive research collection.

Many of our projects involve multiple goals or questions, each of which may be a small contribution in itself, but which plays a critical role in illustrating a bigger picture. This means that well-trained undergraduate students often have the opportunity to take on a part of our research program as their own, becoming the primary individual responsible for that component of the program. This style of research (with many small independent projects working in a larger system of objectives) is ideal for students becoming involved in research for the first time: they get to experience truly independent thinking, analysis, and ownership of their project, but under the guidance of mentors who can help them fit that research into a broader scope and context. I anticipate that those students who display a deep commitment to their work will be able to present the results of their research at national meetings, and become authors of scientific manuscripts that incorporate the results of their independent research.

Undergraduate students involved in our program should expect to commit 10-15 hours per week to research activities, including participation in our weekly lab meetings, and participation in a weekly research seminar focused on introducing beginning students to the basic practices of animal behavior research. Students will also need to complete basic training for working with live animals, and will be expected to devote some nights and weekends to field research in and around San Diego County. Beginning students will gain research experience by working on research projects already underway, overseen by myself, my graduate students, and advanced undergraduates. Students who demonstrate adequate progress through the program will be able to then undertake their own independent research projects.


Student: Geoffrey Ramirez
Title: Chemosensory prey preferences in rosy boas, Lichanura trivirgata
Summary: Many snakes rely extensively on chemosensory information to identify and locate their prey. The degree to which snakes respond to chemosensory cues derived from their prey is often used as a measure of predatory specialization. Evidence from previous studies suggest that Eryicine boas native to North America (the rubber boa and the rosy boa) specialize on preying upon the nestlings of small rodents (mice, voles, rats, and rabbits). Our goal in this project is to examine the chemosensory behaviors of captive-raised rosy boas to determine whether they exhibit strong responses to chemosensory cues from nestling rodents, as opposed to adult rodents that have no nestlings. To accomplish this goal, we examine the responses of rosy boas to clean nesting material, nesting material soiled by rodents with no dependent young, and nesting material from mothers that are currently rearing litters of dependent offspring.


Student: Brittany Sabga
Title: Examining Individual Handedness in Captive Siamangs (Hylobatidae syndactylus)
Summary: Recent research examining handedness in nonhuman primates has revealed that hand preference exists at both the population and individual levels, dispelling the historical belief that handedness is a uniquely human trait. Expanding our understanding of manual lateralization in nonhuman primates will provide insight into the laterality of function in the human brain. In the past three decades, research into this topic has greatly increased in three main primate species, the gorilla (Gorilla gorilla), orangutan (Pongo pygmaeus pygmaeus) and the chimpanzee (Pan troglodytes). Recent research has not revealed a unilateral preference across populations and has failed to reach a consensus on the presence of handedness in these species. Additional research into manual lateralization in a range of nonhuman primate species is necessary to reach a firm conclusion on handedness in nonhuman primates as a whole. Many gibbon species are known to walk bipedally both in captivity and in the wild, which makes them excellent candidates for handedness studies. The present study examines hand preference in 3 captive siamangs at the San Diego Zoo. This study seeks to determine if this population exhibits a significant hand preference across four behaviors, 1) spontaneous feeding, 2) grooming of self and others, 3) brachiation initiation, and 4) the primary hanging hand.


Student: Sierra Stephens
Title: The genetic diversity of an isolated population of timber rattlesnakes, Crotalus horridus
Summary: Genetic diversity is essential to the long-term survival of populations. Populations that are isolated, with no genetic connectivity or dispersal of individuals from nearby populations, can rapidly lose genetic variation through genetic drift and inbreeding. Inbreeding depression is exacerbated in many populations by the increasing rate of anthropogenic habitat fragmentation. Therefore, measuring the extent of inbreeding depression and genetic variation should be of primary concern for isolated populations. Timber rattlesnakes (Crotalus horridus) are medium-sized pitvipers inhabiting the deciduous forests of eastern North America that were formerly abundant and widespread throughout the eastern United States, with a range that extended northward into Vermont, New Hampshire, and Maine. Within the last century, timber rattlesnake populations have undergone widespread declines and range contraction; the species has been extirpated from Maine, and only one known hibernaculum exists in New Hampshire. The remaining New Hampshire population is isolated from any other known population by ~50 miles, well beyond the range over which individuals could emigrate. In this study, we use selectively neutral microsatellite markers to examine the genetic diversity of the only remaining hibernacula of timber rattlesnakes in New Hampshire. We compare the genetic diversity of the New Hampshire hibernaculum to six hibernacula found in northern Adirondack area of New York, which are connected to each other by relatively intact habitat.


Dr. Clark

Department of Biology

Mail Code: 4614
p. 619-594-1527
f. 619-594-5676


Curriculum Vitae

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