A Wisconsin team goes on the hunt for the elusive and endangered massasauga rattlesnake

·7 min read
An eastern massasauga rattlesnake crawls over woody debris in a Wisconsin field.
An eastern massasauga rattlesnake crawls over woody debris in a Wisconsin field.

JACKSON COUNTY - The search started when the morning was young and the air was cool. The aroma of sweet tea lingered in the Jackson County forest openings.

But it was now into the fourth hour and at the third site.

Time and conditions were working against us.

Mother Nature had delivered a "dog day" of August; the sun rose into a clear sky and the mercury climbed into the 90s.

While the heat might draw out beach goers it was apt to have the opposite effect on cold-blooded creatures that could find all the warmth they need under cover.

And though our crew had logged dozens of interesting finds, including an eastern hognose snake and a five-lined skink, the target species had yet to be seen.

Until 11:10 a.m., that is.

"Snake!" said Bridget Rathman, a wildlife biologist with the Wisconsin Department of Natural Resources.

The group slowly converged around Rathman in the swampy forest opening.

There, in a tangle of roots, dead wood and grass on a hummock about the size of a pitcher's mound, coiled a 2-foot-long snake.

Its skin was supremely camouflaged with dark-brown, saddle-shaped blotches against a lighter brown background. Its head was triangular, its neck thin.

The shy reptile stayed low amongst the vegetation, barely visible but conspicuous by a soft, buzzing sound given off by its vibrating tail.

This was the object of our quest: an eastern massasauga rattlesnake.

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Searching for massasauga rattlesnakes in Jackson County

I joined a group of a dozen DNR employees and interns Aug. 10 to look for the endangered snake at an index site in Jackson County.

The outing was led by the DNR's Rory Paloski, a conservation biologist and herpetologist, and Rich Staffen, a conservation biologist and zoologist. Both work in the agency's Bureau of Natural Heritage Conservation.

The eastern massasauga is a relatively short, heavy-bodied snake, typically from 20 to 32 inches in length. It's a pit viper, so-called due to the heat-sensing pits between its eyes and nostrils used to detect prey.

Massasaugas primarily prey on small rodents such mice and voles, but will sometimes eat frogs and other snakes.

And yes, like all vipers, it's venomous. But humans in Wisconsin have more to fear from lightning strikes than massasauga bites.

"(Massasaugas) typically want to get away, to get under cover," said Staffen, who has handled dozens of the snakes. "Our greatest challenge is finding them."

Wisconsin Department of Natural Resources staff conduct a survey for eastern massasauga rattlesnakes in a Jackson County field.
Wisconsin Department of Natural Resources staff conduct a survey for eastern massasauga rattlesnakes in a Jackson County field.

Two native rattlesnakes in the Badger State

Many Wisconsinites are surprised to learn the state has rattlesnakes at all. In fact the Badger State has two native rattlesnakes, the eastern massasauga and the timber rattlesnake.

The timber rattlesnake is larger than the massasauga and is typically marked with dark bands rather than blotches.

The species also occupy very different habitats, with the timber rattlesnake primarily an upland snake and the massasauga more associated with wetlands.

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Massasauga is translated from Ojibwe to mean "great river mouth," likely a reference to the grasslands surrounding river deltas. A modern nickname for the massasauga,  "swamp rattler," is also drawn from its preferred habitat.

The historical range of the species included New York, western Pennsylvania, southeastern Ontario, Michigan, Ohio, Indiana, Illinois, Wisconsin, Minnesota, east central Missouri and eastern Iowa, according to the U.S. Fish and Wildlife Service.

As was the case with many species deemed threats to European settlers in Wisconsin, a bounty was placed on the massasauga.

The cash payment in exchange for dead snakes no doubt hastened the species' decline. Habitat loss, in part due to hydrologic changes, also has negatively affected the massasauga.

Wisconsin rattlesnake bounty ended in 1975

The state bounty was active until 1975, the same year the massasauga was placed on the Wisconsin list of endangered species.

Paloski said there are only eight Wisconsin sites known to still hold massasaugas.

"And we don't know is if those are viable populations, including if they are genetically viable," Paloski said.

In 2016 federal officials acknowledged a significant decline in eastern massasauga populations and classified the species as threatened under the Endangered Species Act.

Most of the remaining massasauga populations are in Michigan and Ontario, according to the USFWS.

The species is also still found in New York, Pennsylvania, Ohio, Indiana, Illinois, Iowa and Wisconsin. But these states have fewer and more isolated populations of the snake, according to the agency.

The species has been documented in recent years at eight sites in Wisconsin, mostly in the southern and western portions of the state.

Because of the inclination by some humans to exploit or abuse the snakes, the specifics of the locations are not disclosed to the public.

The Wisconsin DNR work to preserve massasaugas includes long-term monitoring, historic site surveys and habitat management, Paloski said.

As a result of the federal listing the Wisconsin DNR this spring started an annual survey for massasaugas at the Jackson County index site.

The work, conducted according to USFWS protocols, involves five days of spring surveys at the site each year for five years, then once every five years.

48 massasaugas captured in the spring

The primary purpose of these surveys is to collect demographic information and to monitor the population over time. Forty-eight massasaugas were captured this spring at the site and marked with passive integrated transponders (or PIT tags).

The PIT tags will allow a mark-and-recapture study and a potential population estimate.

The surveys also provide behavioral data, habitat preferences and overwintering areas.

Each state with known massasauga populations is doing the same work, Staffen said.

The DNR is also looking for massasaugas at locations in Wisconsin where the snake used to be found but hasn’t been recorded in decades.

Eastern massasaugas use shallow wetlands and surrounding upland areas to forage, breed, shelter and hibernate. They don't migrate but are known to move about one-quarter mile or less.

And together with partners, including foresters in its agency, the DNR is helping improve habitat for massasaugas by keeping open canopy intact in forests and adding structure such as downed logs and other woody debris.

A grasping tool on the end of a hiking or golf club shaft is used to handle snakes in surveys.
A grasping tool on the end of a hiking or golf club shaft is used to handle snakes in surveys.

Our crew continued to look around the bases of trees and in deadfalls for the snakes. We used staffs with a gripper device on the end to probe into the vegetation.

The massasauga located by Rathman was clearly in choice habitat.

Its hummock was part of a wetland spiked with tamarack saplings and carpeted with wild cranberries. After tolerating our gaggle of onlookers for a minute, the snake slipped lower into the tangle and out of sight.

It turned out to be the only massasauga we found on the outing.

Staffen said it was very likely others were around but stayed low in the hot conditions.

There was no need for the snakes to bask in the sun to get warm when the ambient temperature of the swamp was in the 80s.

Paloski said the massasauga encountered could be a gravid female about to give birth.

Massasaugas are "live birthers" and typically have litters of five to 20 snakes in August. The offspring are about 7 inches long.

"We'll be back next year, and maybe we'll see that snake again or its offspring," Paloski said. "It's critical for us to know where the snakes are so we can conserve and manage for them."

This article originally appeared on Milwaukee Journal Sentinel: Wisconsin scientists search for elusive massasauga rattlesnake