Federal regulators have requested that the eastern massasauga rattlesnake, one of Minnesota’s two venomous snakes, be designated as a threatened species.

The U.S. Fish and Wildlife Service said Tuesday the snake’s population is dwindling throughout the Upper Midwest and Canada, primarily because of loss and fragmentation of its habitat, which includes wetlands such as swamps, bogs and marshes.

The eastern massasauga, also known as the spotted rattler or swamp rattler, has disappeared from 40 percent of the counties it historically inhabited from western New York through sections of Pennsylvania, Ohio, Michigan, Illinois, Indiana, Wisconsin, Minnesota, Missouri and Iowa.

Although the species is found in western Wisconsin, survey records from the Minnesota Department of Natural Resources (DNR) show that it hasn’t been spotted in the state for nearly 80 years — since 1936.

“Biologists have simply not been able to find it anywhere, so it appears to be extirpated from the state. It’s not a snake that will have any consequences for Minnesota,” said Carrol Henderson, head of the DNR’s nongame wildlife program.

“We don’t have the extensive lowland, backwater-types of habitat that this snake needs,” Henderson said. “In the distant past we’ve had records of that snake, but not anymore.”

The massasauga is a small rattlesnake, typically about 2 feet long, with a heart-shaped head, vertical pupils and a tail with dark brown rings tipped with gray-yellow rattles. It is listed as endangered, threatened or a species of concern under state law throughout its range and has been a candidate for federal listing since 1999.

Henderson said Minnesota’s only other venomous snake, the timber rattlesnake, is more prominent and is the one that residents in the southeastern part of the state are likely to come across.

Rattlers are “poorly underappreciated” for their role in controlling the small rodent population, he said, and DNR officials encourage Minnesotans to leave them alone. Most are thought to be _docile, secretive reptiles.

Members of the public have 60 days to comment on the proposed listing, either online or by mail.

 

The Associated Press contributed to this report.