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

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

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.

Veterinary Care: Water Monitor Exam

Dr. Ann Duncan is the Chief Veterinarian for the Detroit Zoological Society.

We recently performed an examination on our new water monitor. He is a 5-year-old adult male, weighs 30 pounds and is approximately 6 feet long. Water monitors are native to parts of southeast Asia. They are not an endangered species, but are known to be exploited in the pet trade. We rescued him from a local rescue organization that recently lost its funding, and he is currently in quarantine to ensure he is free from health problems before he is moved to the Holden Reptile Conservation Center.

All animals new to the Detroit Zoo undergo a quarantine period; this is a very important practice that allows close observation, acclimation to new diets and caretakers, and ensures we do not transfer any contagious diseases to the rest of the resident animals.

Many of our snakes and lizards can be held by trained zookeepers while we examine them thoroughly and collect blood and other samples for testing. They can often even be radiographed while resting quietly on an X-ray plate. Our new water monitor is a very large lizard, and we knew it would not be possible to hold him safely for his exam. Water MonitorDr. Wynona Shellabarger created a plan for the monitor’s examination, and then went to his holding area to administer a sedative to allow for a safe and calm trip to the hospital. Once there, he was given gas anesthesia through a facemask until he was sedated enough that we could position him for radiographs and safely examine him. We palpated his abdomen, muscles and joints, listened to his heart and lungs, and examined him from head to toe, including the inside of his mouth. We also performed an ultrasound exam of his heart and other abdominal organs.

He appears healthy and in good condition. We will continue to “monitor” him until his quarantine period has ended and his new habitat at the Holden Reptile Conservation Center is ready for him.

– Dr. Ann Duncan