eastern massasauga rattlesnake

Notes from the Field: Protecting Michigan’s Only True Venomous Snake

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Michigan is the last stronghold for the massasauga rattlesnake – even though the species was listed as Threatened by the U.S. Fish and Wildlife Service, there are still several healthy populations throughout the state. The Detroit Zoological Society oversees the Species Survival Plan for this animal through the Association of Zoos and Aquariums (AZA). These comprehensive population management plans work to ensure the sustainability of healthy, genetically diverse and demographically varied captive animal populations.

The DZS and other facilities have participated in an ongoing research study at the Edward Lowe Foundation in Cassopolis, Mich., for the past 10 years. Recently, a team from the Detroit Zoological Society, which also included Jeff Jundt, curator of reptiles, and Dr. Wynona Shellabarger, a veterinarian for the Ruth Roby Glancy Animal Health Complex at the Detroit Zoo, participated in the 2018 Eastern Massassauga Rattlesnake Species Survival Plan annual meeting and conducted fieldwork in western Michigan.

This fieldwork consists of spending up to eight hours a day searching for snakes in their native habitat. When one is found, it is sent to a lab on grounds for a physical, which includes being weighed, measured, photographed, sexed, tagged with what is called a passive integrated transponder – if it didn’t have one already – and having blood collected. If the snake is female, it’s given an ultrasound to determine if she’s pregnant. Photographs of any distinct markings as well as the transponder can identify an animal throughout their life if they are located again. GPS data allows the snake to be returned to the exact spot where it was found earlier in the day.

All of the information gathered throughout the week helps draw a picture of the natural history of this species, guide best practices for the land management of the Edward Lowe Foundation and gauge the overall health of the individuals and the population. This year, even though the weather was not as cooperative as past years, the group was able to locate and conduct physicals on 36 snakes, 14 of which were new to the study. The DZS plans to continue leading this important research for years to come. To stay up to date on all things massasauga rattlesnake-related, follow the Species Survival Plan on Facebook.

Also, please join us as we celebrate all things that slither on World Snake Day, Monday July 16, in the Detroit Zoo’s Holden Reptile Conservation Center.

– Rae Karpinski is a reptile zookeeper for the Detroit Zoological Society.

Notes from the Field: Monitoring the Eastern Massasauga Rattlesnake

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The Detroit Zoological Society (DZS) leads the Eastern massasauga rattlesnake Species Survival Plan (SSP), which is a comprehensive management plan through the Association of Zoos & Aquariums (AZA) that works to ensure the sustainability of healthy, genetically diverse and demographically varied captive animal populations. The DZS is also one of several organizations within the AZA that participates in a long-term study of a particular population of Eastern massasauga rattlesnakes in Michigan.

The Eastern massasauga rattlesnake is the mitten state’s only venomous viper, and is listed in Michigan as a species of special concern, which means it is threatened or endangered throughout its range. This SSP is a special one because each year, representatives from participating zoos attend a meeting in conjunction with an “in situ” study, which means that it takes place in the field.

This year marked our eighth monitoring a particular population of Eastern massasauga rattlesnakes in the southwest part of the state, and it was our best year to date – we found more than 100 snakes! This includes snakes that were found in previous years as well as newly identified individuals. The process involves gathering information on each snake in the field and then taking it to a lab where it is weighed and measured. We also determined if it is a male or a female and if female, whether it is pregnant (massasaugas give birth to live young). If the snake has never been found before, it is marked with a transponder tag – similar to those implanted in your pet dog or cat – so we can scan the animal and take measurements if it is found in the future. After the information has been gathered in the lab, the snake is then returned to the exact location where it was found.

Monitoring a seemingly healthy population over time gives us insight into natural fluctuations of the population size, male-to-female sex ratio, individual growth rates and reproductive success. As years goes by, the data will also begin to tell us life history data such as longevity of the species and how old animals remain reproductively active. All of this information assists the AZA zoos in how they manage the captive population as well as the state departments of natural resources in their management of the wild populations and the lands on which they are found.

– Jeff Jundt is the curator of reptiles for the Detroit Zoological Society and oversees the Holden Reptile Conservation Center at the Detroit Zoo.