Rattlesnakes marrying cousins? Michigan’s venomous snake faces extinction risk from inbreeding, study warns

Study Reveals Inbreeding Crisis in Michigan’s Venomous Snake (Image: Canva)

A snake that keeps wetlands in balance is now fighting for survival. Scientists say the Eastern Massasauga rattlesnake, Michigan’s only rattler, is being pushed towards decline by inbreeding.

Why is inbreeding threatening the rattlesnake?
A 15-year study by Michigan State University found habitat fragmentation is forcing snakes to mate with close relatives. Roads, farms and buildings are dividing wetlands into isolated patches, leaving the species vulnerable.

Researchers built detailed family trees of more than 1,000 snakes, captured and released over years of fieldwork. Their findings show inbred snakes were 13% less likely to produce surviving young and had 12% lower annual survival.

“These populations are fairly large and stable, yet we’re already seeing the negative effects of inbreeding,” said Sarah Fitzpatrick, lead author of the study published in the Proceedings of the National Academy of Sciences.

How do rattlesnakes support wetlands?

Eastern Massasaugas are keystone predators, playing a crucial role in controlling rodent populations. Their decline could upset the delicate balance of wetland ecosystems, which also support nearby farms and homes.

The species rarely strays far from its natal wetlands, and human development is restricting its range even more. “Even a single road can isolate populations,” Fitzpatrick said.

What can protect these snakes?
Scientists say urgent conservation steps are needed to restore habitat connectivity. Road underpasses, wetland restoration and even relocation could help maintain genetic diversity and stabilise populations.

Researchers used genomic sequencing and PIT tagging to track reproduction and survival. Each year teams returned to wetlands, braving harsh conditions to monitor the rattlesnakes before releasing them back.

Though often feared, Eastern Massasaugas are vital for Michigan’s natural systems. Protecting them, scientists argue, ensures wetlands remain healthy for generations to come.