Toni Ziegler, expert on nonhuman primate hormone assays, retires

Toni Ziegler, Ph.D. head shot
Toni Ziegler, Ph.D.

Amidst a small gathering of friends and coworkers keeping their distance from one another on March 14, 2020 at the Fluno Center, UW–Madison Distinguished Scientist Toni Ziegler celebrated her retirement as head of Assay Services at the Wisconsin National Primate Research Center. Many of us will remember this as our last event before hunkering down and so we wish Toni many more celebrations and long overdue hugs with her family and friends soon! 

We begin our tribute to Toni by sharing words from Chuck Snowdon, Professor Emeritus of Psychology, from that night:

“Thirty-eight years ago at an International Primate Congress, I met a young graduate student who was completing her degree in veterinary anatomy and physiology and studying marmosets at Texas A&M. I had recently had a grant funded to study reproductive biology in cotton-top tamarins. We had a great conversation and I offered her a job. In January, 1983, she moved from toasty Texas to wintery Wisconsin, never thinking that she’d stay here the rest of her working life. In the subsequent years Toni has moved from starting as a post-doc to finishing as a distinguished scientist and permanent PI.

Her scientific accomplishments are many. She has published at least 242 papers and abstracts and according to Google Scholar she has an H score of 54, which means 54 papers have been cited at least 54 times each. In fact she has nearly 9,500 citations to her work. According to Research Gate she ranks in the top 2.5% of all researchers in her impact.

She has made her mark in many ways. As a developer of noninvasive hormonal and other assays she has developed the gold standard for assay validation (while others admit they get by with backpack standards). She has worked with captive primates, but has also been one of the pioneers in working with field researchers to develop and validate assays that can be used in the field. She has been incredibly generous in sharing her expertise and training others. There are now assay labs in Europe and in Brazil that exist because Toni trained the directors. By my count, she has developed assays for use with 33 primate species including at least 15 that are endangered.  Many of the field researchers have been graduate students who have gained invaluable skills through working with Toni.

Toni holding a vintage framed marmoset print, a gift from Chuck Snowdon
Chuck Snowdon’s retirement gift to Toni

Toni and I have co-authored over 40 papers, and her collaboration was very important to the success of our reproductive research with cotton-top tamarins. We shared the supervision of several graduate students and they, and many undergraduates, developed assay skills through Toni’s teaching. Together we have also explored the role of chemical signals in tamarin and marmoset behavior, collaborated on the first study to do functional brain imaging in marmosets, studied the role of oxytocin and prolactin in family members other than mothers in our cooperatively breeding species and much more.

When the first woman in my lab to have a baby brought in her infant, she coached all the women on how to hold the infant, but when my turn came, her first words were ‘Chuck, you’re so clumsy.’ In contrast, when I visited Toni after her son Travis was born, she handed him to me with no criticism. Mothers of cooperative breeders must be willing to share child care and Toni has proven herself to be a good Callitrichid-style mother.

Finally, over the years Toni has also been a good friend as well as a good colleague. We have helped each other in both sad and glad moments.

I am happy to celebrate the work life of Toni Ziegler and wish her a very happy and healthy retirement. Toni, here is a 250-year old memento of our shared work for you to remember us by.”

Karen Strier, UW–Madison Vilas Research Professor, Irven DeVore Professor of Anthropology and President of the International Primatological Society also spoke at the gathering. Strier is an international authority on the endangered northern muriqui monkey of Brazil.

“I first met Toni Ziegler in 1988, when she visited my field site during an IPS meeting. She was a post-doc with Chuck Snowdon working on the reproductive endocrinology of cotton-top tamarins and was visiting with him, Fred Bercovitch and Frans de Waal. Toni and I began talking about muriqui reproduction, and I lamented that it was limited to what I could observe about their mating behavior relative to the birth of infants because I didn’t want to consider any kind of invasive research. Toni said, “I bet we can do it  noninvasively!” And thus began what became our 15-year non-invasive fecal steroid study.

Through this study, we developed new ways to measure reproductive and stress hormones to learn more about these animals. Understanding the mechanisms underlying muriqui fertility had obvious important implications for conservation efforts on their behalf.

Toni Ziegler and Karen Strier in the Primate Center’s Assay Services lab in 2002.
Toni Ziegler and Karen Strier in the Primate Center’s Assay Services lab in 2002.

Toni came back to visit my field site with me a few more times and  on one we collected fecal samples in the forest together. She is a great traveler and we’ve made many trips to IPS and other meetings together. We have also shared in many celebrations together: the births of both of her sons, and even her first private office! We also formed a special bond because we were both young women scientists trying to establish our research careers, so we could really relate to one another.

Toni is always optimistic; she believes in people and she is kind. If I were reincarnated as a captive primate, I would want to be in Toni’s lab. If I were a kid, I would want her as my mom.

Toni believes in all of us, she helps us to be the best we can be. And I cannot wait to see what new adventures this new phase of her life brings!”

After Toni completed her post-doc with Chuck Snowdon, she worked her way up to associate scientist in the Department of Psychology and also at the Primate Center. She became co-director of Assay Services with David Abbott in 1994, was appointed senior scientist in 1997, then head of Assay Services at the Primate Center and the Institute for Clinical and Translational Research in the early 2000s. She earned her Distinguished Scientist title in 2015.

“Toni’s impressive scholarly reputation in the areas of primate behavior and neuroendocrinology were well known to me prior to my own transition to the Center,” says Jon Levine, Director of the WNPRC since 2010. “When I arrived, however, I rapidly realized that she was truly a “triple-threat” in terms of her value as a WNPRC scientist – her scholarship, her collaborative spirit, and her technical expertise in developing and maintaining a world-class assay services unit are woven into a scientific force that will be deeply missed at the Center, and by her national and international colleagues.”

In addition to garnering more than two dozen research grants and awards over her career and the resulting large body of publications, she has served on several NIH review, WNPRC and UW–Madison committees, as well as professional society and editorial boards, including serving as executive secretary for the American Society of Primatologists and hosting the Society’s meeting in Madison Wisconsin, August 2019.

Finally, we have some additional words from Toni herself:

“From the time I came to UW-Madison for post-doctoral work, I found it an honor to be working at such a prestigious university.  Not only was I able to establish a career trajectory at the university but I was privileged to collaborate with so many world class scientists and faculty. It was an amazing opportunity to learn from so many specialists such as Professor Charles Snowdon on methods for behavioral data and understanding vocalizations in primates; from Professor Karen Strier on life histories and field studies of nonhuman primates; from Seth Pollack on his work with institutionalized children; from Guenther Scheffler who ran the steroid lab in Assay Services on the best methods for validation of hormone assays, and from Fritz Wegner who was an expert in peptide and protein assays. Many other exceptional scientists gave of their time when I first started working at the Primate Center, such as Sam Sholl, William Bridson, Robert Matteri and Hideo Uno. Thanks to Joseph Kemnitz and Marc Drezner, I was able to lead Assay Services as a core lab for the Institute for Translational and Clinical Research (ICTR), where I collaborated with many scientists and physicians on important and fascinating biomedical clinical research.

My other unique opportunity was to be able to work with so many exceptional undergraduate and graduate students, scientists and research specialists who trained in the assay lab. The graduate students who came to learn the art of assays for their own projects brought another level of enjoyment to the entire laboratory.  Students came from throughout the United States but also from as far away as Germany, England, Switzerland and Brazil.

I will always look fondly on my colleagues at the WNPRC — the research staff, the caretakers, vet staff, and all the business staff who keep the primate center running!

(Story editing and photos by Jordana Lenon. Marmoset framed print photo by Sofia Refetoff.)


An infant marmoset monkey clings to his father at the Wisconsin National Primate Research Center.
An infant marmoset monkey clings to his father at the Wisconsin National Primate Research Center. The monkeys were part of a 2008 study by WNPRC scientist Toni Ziegler showing that the odor of their own offspring lowers testosterone levels in marmoset fathers.