I was born and raised in Columbia, South Carolina. Encouraged by my parents (Romeo and Susie Hayes) and inspired by the wildlife around me, hiking in Congaree Swamp, reading National Geographic Magazine, and watching the television show “Wild Kingdom”, I developed an interest in biology very early in my childhood. In particular, I was fascinated by amphibians and the influences that environmental changes have on their development, growth, and reproduction.
What you

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Tyrone Hayes


1. Biography

2. Curriculum Vitae

3. Speaking Schedule

4. Links to Radio

5. Links to Documentaries

6. Links to Videos

7. Other Links

8. Contact Tyrone Hayes


After graduating from Dreher High School in 1985, I attended Harvard University. I graduated from Harvard in 1989 after writing an honor’s thesis (for which I received summa cum laude recognition) on the influence of temperature on larval growth, development, metamorphosis and sex differentiation in woodfrogs. I then entered the Department of Integrative Biology at the University of California, Berkeley to obtain my PhD. For my doctoral dissertation, I examined the role of hormones in mediating developmental responses to environmental changes in amphibians. I completed my doctoral work in 1993 and began post-doctoral studies at the National Institute of Child Health and Human Development, National Institutes of Health and the Cancer Research Laboratories, UC Berkeley (funded by the National Science Foundation), where I examined molecular mechanisms of hormone action in amphibians. In 1994, I joined the faculty at Berkeley as an Assistant Professor. In 1998, I was appointed Associate Professor with tenure at Berkeley, becoming the youngest tenured professor in the department and then in 2002 was promoted to full Professor at age 35, likely the youngest full professor in the University. In addition to my main appointment in the Department of Integrative Biology, I also hold joint appointments in the Museum of Vertebrate Zoology, the Group in Endocrinology, the Molecular Toxicology Group, and the Energy and Resources Group. In these capacities, I have directly trained more than 60 students in my laboratory in addition to having taught more than 1500 in the classroom over the last 12 years. Among other awards, I have received both the Distinguished Teaching Award and the Distinguished Mentor Award from the University of California at Berkeley, the Jennifer Altman Award for Integrity in Science (Jennifer Altman Foundation), the Rachel Carson Memorial Award (Pesticide Action Network), the National Geographic Emerging Explorer Award (NGS), the President’s Citation Award (American Institute of Biological Sciences), and January 24, 2005 was proclaimed “Dr. Tyrone Hayes Day”, by the Mayor of the City of Minneapolis, Minnesota.

My primary research focuses on the role of environmental factors on growth and development in amphibians. I have published more than 40 papers, over 150 abstracts, and have given more than 300 talks on this topic. Through my research, I have come to realize that the most important environmental factors affecting amphibian development are synthetic chemicals (such as pesticides) that interact with hormones in a variety of ways to alter developmental responses. Thus, my current research focuses on the effects of endocrine disrupting pesticides on amphibian growth, development, reproduction and immune function and how these studies predict effects in other wildlife and humans.

In 1997, in addition to my work at the University, I began consulting with and conducting research for the chemical company, Novartis (which eventually became the agri-chemical giant, Syngenta Crop Protection). My laboratory showed that the herbicide atrazine (the number one selling product for Syngenta) is a potent endocrine disruptor that chemically castrates and feminizes exposed male amphibians at low ecologically relevant concentrations. The company and their contracted consultants at Ecorisk Inc. were not enthusiastic about my findings and prevented me from presenting these data at scientific meetings, publishing the data, and hindered progress to replicate/validate the data. In 2000, I resigned my consulting position with the company and published my work and further supportive findings with independent funding.

Despite controversy generated by the industry giant (attempts to finance me and keep my work under the control of the corporation and to discredit me and my work), I was promoted to full professor in 2003. Presently work continues to focus on the effects of pesticides on amphibians and the role of this threat in amphibian declines. Furthermore, it has become clear that the adverse effects of atrazine extend beyond amphibians. Through endocrine-disrupting mechanisms identical to those acting in amphibians, atrazine produces effects in other animals, including prostate and breast cancer and decreased fertility in laboratory rodents. These same effects are associated with atrazine exposure in humans. In addition to the scientific interests, this issue is one of environmental justice. Citizens in lower socio-economic classes and, in particular, ethnic minorities are less likely to have access to this information, more likely to be employed and live in areas where they are exposed to pesticides, less likely to have access to appropriate health care, and more likely to die from what are already the number one cancers in men in women (prostate and breast cancer, respectively), with cancer now being the number one cause of death in the US.

Industry has increased efforts to discredit my work, but my laboratory continues to examine the impacts of atrazine and other pesticides on environmental and public health. My decision to stand up and face the industry giant was not a heroic one. My parents taught me, “Do not do the right thing because you seek reward… and do not avoid the wrong thing because you fear punishment. Do the right thing, because it is the right thing.” If I want to raise my own children with the same philosophy, then I have to live my life in accordance with the way that I direct theirs. There was only one choice.

“What you want and what you say should be the same…

Neither future nor past can exist alone.”

Tao Te Ching, Chapter 2

Tyrone B. Hayes, PhD


Laboratory for Integrative Studies in Amphibian Biology

Dept. of Integrative Biology

University of California

Berkeley, CA 94720-3140


Office 510-643-1054

Laboratory 510-643-1055

Fax 510-643-6264


1. What is Atrazine ?

2. Environmental Contamination

3. Ecological Impacts

4. Endocrine disruption

5. Neural Damage

6. Pregnancy loss

7. Reproductive Cancers

8. Endangered Species

9. Risks and Benefits