Gila Monsters
Field Site

Team DeNardo

Emily Taylor



B.A. English, 1998, University of California, Berkeley (UC Berkeley)

Ph.D. Biology, 2005, Arizona State University


Current Position

Associate Professor, Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407.


Doctoral Research Interests

My research interests were environmental physiology, natural history, and conservation of reptiles. I was particularly interested in how environmental and hormonal mechanisms affect the processes of growth and reproduction, and ultimately, sexual size dimorphism.


Dissertation Work

My dissertation research addressed the question, "Why are male rattlesnakes larger than females?" from a mechanistic, physiological viewpoint. My research involved theoretical ideas and techniques from many disciplines, including physiological ecology, endocrinology, and evolutionary biology.

I addressed my research question using a combination of field and laboratory approaches. I studied free-ranging Western Diamond-backed Rattlesnakes (Crotalus atrox) at our field site for four years using radiotelemetry and mark-recapture, and I conducted several laboratory experiments to examine specific factors in a controlled setting. Specific topics I investigated include:

·      reproductive ecology and natural history

·      hormonal regulation of reproduction

·      thermal biology

·      effects of food supplementation on reproduction

·      growth plasticity of snakes in the lab

·      effects of castration on growth

Overall, I found that growth is extremely plastic in C. atrox, with food intake and the energetic cost of reproduction heavily influencing growth. Testosterone does not appear to affect growth in this species, as it does in many other vertebrates. It appears that male C. atrox are larger than females primarily due to differential energy expenditure on reproduction, in which females expend much more energy on reproduction than males, resulting in less energy left over for growth. In a food-limited environment such as the Sonoran Desert, this differential energy expenditure can have profound effects on adult body size and sexual size dimorphism.


Previous Research

As an undergraduate at the University of California at Berkeley, I conducted a research project with Dr. Harry Greene on the feeding habits of the Baja California Rattlesnake.


Publications from work while in the DeNardo lab

Taylor, E. N., and DeNardo, D. F. 2008. Proximate determinants of sexual size dimorphism in the western diamond-backed rattlesnake (Crotalus atrox), In The Biology of Rattlesnakes (W. K. Hayes, K. R. Beaman, M. D. Cardwell, & S. P. Bush, eds.). Loma Linda University Press, Loma Linda, California, Pp. 91-100.


Taylor, E. N., M. A. Malawy, D. M. Browning, S. V. Lemar, and D. F. DeNardo. 2005. Effects of food supplementation on the physiological ecology of the Western Diamond-backed Rattlesnake (Crotalus atrox). Oecologia 144:206-213.


Taylor, E. N. and D. F. DeNardo. 2005. Sexual size dimorphism and growth plasticity in snakes: an experiment on the Western Diamond-backed Rattlesnake (Crotalus atrox). Journal of Experimental Zoology 303A:598-607.  


Taylor, E. N. and D. F. DeNardo. 2005. Reproductive Ecology of Western Diamond-backed Rattlesnakes (Crotalus atrox) in the Sonoran Desert. Copeia 2005:152-158.


Taylor, E. N., D. F. DeNardo, and D. H. Jennings. 2004. Seasonal steroid hormone levels and their relation to reproduction in the Western Diamond-backed Rattlesnake, Crotalus atrox (Serpentes: Viperidae). General and Comparative Endocrinology 136:328-337.


Taylor, E. N., D. F. DeNardo, and M. A. Malawy. 2004. A comparison between point- and semi-continuous sampling for assessing body temperature in a free-ranging ectotherm. Journal of Thermal Biology 29:91-96.


Taylor, E. N. and G. W. Schuett. 2004. Effects of temperature and storage duration on the stability of steroid hormones in blood samples from Western Diamond-backed Rattlesnakes. Herpetological Review 35:14-17.


Schuett, G. W., E. N. Taylor, E. A. Van Kirk, and W. J. Murdoch. 2004. Handling stress and plasma corticosterone levels in captive male Western Diamond-backed Rattlesnakes (Crotalus atrox). Herpetological Review 35:229-233.


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