![\"Eastern](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/08\/Eastern-Massasauga-rattlesnakes-live-in-Michigan-and-other-Midwestern-states-scaled.jpeg\")
Eastern massasauga rattlesnakes live in Michigan and other Midwestern US states. Credit: Eric Hileman
\nEastern massasauga rattlesnake \u2013 clues in the DNA<\/p>\n
Eastern massasaugas are creatures of habit. These small, venomous<\/a> pit vipers rarely leave the wetland where they are born, typically venturing out only to find food or a mate before returning home.<\/p>\n However, as human presence increases across their range, the snakes are even less likely to travel between habitats. Barriers such as roads or farmland can cut off populations completely.<\/p>\n \u201cThey\u2019re very vulnerable to even minor disturbances to their habitat,\u201d says Sarah Fitzpatrick, Michigan State University (MSU)<\/a> professor and one of the senior authors on the study. \u201cEven a single road can isolate populations.\u201d<\/p>\n To see whether this isolation is causing problems for the rattlesnakes, researchers at MSU analysed 1,056 individuals collected over 15-year period across two counties in south-west Michigan: Cass and Barry.<\/p>\n The team looked at each captured snake\u2019s length, weight and pregnancy status. They also used blood samples taken at the time of capture to extract DNA and sequence their genomes, which then allowed the researchers to work out how closely any two individual snakes were related. <\/p>\n They found that the most inbred individuals were 13% less likely to have offspring that survived, and had a nearly 12% lower annual survival rate than healthy, less inbred snakes.<\/p>\n \u201cThese are fairly large and stable populations of eastern massasaugas,\u201d says Fitzpatrick. \u201cThe fact that we\u2019re detecting problems from inbreeding in these populations is concerning, given that many other populations throughout the Midwest are much smaller and even more fragmented.\u201d<\/p>\n Why is inbreeding bad?<\/p>\n The findings paint a troubling picture for the future of these snakes, says Meaghan Clark, the study’s lead author and a former MSU graduate student.<\/p>\n Inbreeding reduces the ability for an animal to survive, reproduce and pass on its genes. Biologists have long suspected this so-called ‘inbreeding depression’ takes place in the wild, but it is difficult to prove, especially in elusive species such as rattlesnakes.\u00a0<\/p>\n Eastern massasaugas play a vital role in wetland ecosystems across the Midwest. They are skilled hunters of rodents such as mice and rats<\/a>, keeping numbers under control and preventing infestations in nearby barns and homes, says Clark. \u201cIf rattlesnakes disappeared, the entire balance of the ecosystem would be disrupted.\u201d<\/p>\n What’s next?<\/p>\n The researchers say this study provides rare evidence from natural populations that the consequences of inbreeding, caused by isolation, are both measurable and significant.<\/p>\n![\"Researcher](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/08\/1755851290_243_image.jpeg\")
Researchers used snake tongs to catch eastern massasauga rattlesnakes for their 15-year study. Credit: Sarah Fitzpatrick
\n![\"Researchers](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/08\/Researchers-catch-Eastern-Massasauga-rattlesnakes-every-summer-as-part-of-a-15-year-study.jpeg\")
The length, weight and pregnancy status of each snake was taken, as well as a blood sample, which the team used to extract DNA. Credit: Sarah Fitzpatrick<\/p>\n![\"Eastern](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/08\/Eastern-Massasauga-rattlesnakes-live-in-Michigan-scaled.jpeg\")
The eastern massasauga rattlesnake is listed as threatened under the Endangered Species Act. Credit: Eric Hileman<\/p>\n