Snake Trek

A first-person account by Kristen Ortiz, Venomous Reptile Keeper

For a zoo keeper passionate about our reptile friends, no spring would truly be complete without an annual trek to southwest Michigan to get covered in mud (but hopefully NOT poison sumac and ticks) to search for one of the Midwest’s most endearing native venomous snakes, the eastern massasauga rattlesnake (Sistrurus catenatus).

This year, the group from Lincoln Park Zoo also included Lisa Faust, Ph.D, the zoo’s Senior Director of Population Ecology and the Eastern Massasauga Species Survival Plan (SSP) Field Conservation Advisor; Dan Boehm, Curator and the SSP’s Studbook Keeper; and Rachel Bladow, Population Biologist. We attended an event that has become a longtime tradition for Association of Zoos and Aquariums members interested in eastern massasauga rattlesnake conservation.

Weighing only a few hundred grams, the eastern massasauga rattlesnake is a federally protected species currently listed as “Threatened” under the Endangered Species Act as of 2016. These snakes prefer wetlands areas such as wet prairies and marshes rather than forests or the deserts of the Southwest, like other native North American pit vipers.

In 2009, Joanne Earnhardt, Ph.D., at the time the zoo’s director of the Alexander Center for Applied population Biology, and Lisa Faust, Ph.D., formed the Eastern Massasauga SSP with member zoos around the country and in Canada. They then partnered with Northern Illinois University, wildlife agencies, and the Edward Lowe Foundation, which owns a property in Michigan and hosts the SSP. Each spring, AZA member institutions collaborate to monitor the snakes at this site, which happens to be a central location within the species’ range.

Since then, more than 1,000 eastern massasauga snakes have been captured, examined, identified, and released as they emerge from hibernation in the spring. Monitoring these individuals over time helps researchers understand demographics, population trends, disease risk, and the impact of wildlife management actions.

Marking the 15th year of this study, more than 33 attendees from 23 different institutions gathered once again to devote our time and energy to this well-loved reptile species. We spent long, 10-hour days hiking up to five miles a day in search of these cryptic pygmy snakes. Although we ended up with tired leg muscles, our laser-focused search efforts yielded 55 snakes—including 36 new animals and 19 recaptures. In past years, we’ve found as few as 12 snakes and as many as 117. With all these individuals, we identify the ones that we’ve seen before and place PIT tags, or ID chips, in the new captures.

One of our recaptures was the buzz of the week, as she was the oldest individual in the program. The female eastern massasauga snake was first seen as a yearling 12 years ago, making her 13 years old. And this marks the seventh time we’ve seen her! We are grateful to her for giving us very valuable data on longevity of this species, as well as confirmation that this habitat continues to provide the ideal conditions and resources necessary to promote a thriving population.

We process the data we receive from each animal, including size, weight, and growth information. We also take blood samples to study hormone levels, nutrients, genetics, and more. The data we’ve collected from each individual over these 15 years has provided us—and will continue to provide us—with invaluable information in helping us understand how to better monitor and preserve all populations across the range.

To round out the week, the group also had its annual SSP meeting to make future plans for all the eastern massasaugas currently housed in zoos around the country. This involves discussing breeding and transfer recommendations, considering husbandry needs, and reporting on research findings. Ultimately, these tasks help to better maintain a healthy, thriving population of massasaugas in AZA zoos, so they can serve as ambassadors for their endangered counterparts.

We also talk about education and outreach efforts to help more people understand and appreciate these amazing creatures. We’re excited about the impact we’re making in eastern massasauga conservation and look forward to continuing this tradition next year!