As is the Timber Rattlesnake across its range in the Eastern USA, the Eastern Massasauga Rattler is similarly threatened across its range of central New York and southern Ontario to south central Illinois and eastern Iowa................So it is with most other animal species that we human animals encounter, our land alteration practices and state and local bounties have hammered this snake population to perilous levels--designated as "threatened" under the Federal Endangered Species Act....................""In Illinois, they've nearly blinked out entirely"................ "We're probably down to one location in the southern part of the state that has a stable population".............. "They seem to have stronger holds in Michigan and southern Ontario"....................A warming climate has also been no friend to the Massasauga.................."Litter sizes decreased with increasing mean temperature, and increased by one offspring for each 1.89-degree increase in latitude, even when maternal size was held constant"

https://www.google.com/url?rct=j&sa=t&url=https://phys.org/news/2017-02-life-history-imperiled-rattlesnake.html&ct=ga&cd=CAEYASoSODA1Mjc5NTc2MTU4Mjk5OTE2MhphYmIyYzE1MzZhZjZhZDUzOmNvbTplbjpVUw&usg=AFQjCNF5R4GGEMYcqmEyRaXdHl015GTh4A

Study examines life history of imperiled rattlesnake

February 16, 2017 by Tom Parisi

A new study is bringing attention to a little known and imperiled rattlesnake that slithers among the wetlands in regions surrounding the Great Lakes.

The Eastern Massasauga rattler was once common in such states as Indiana and Illinois.. Until recent years, it could still be found in Chicago's Cook County. But the reptile's range and numbers have been steadily declining. In 2016, the snake was listed as threatened under the U.S. Endangered Species Act.

In the new study, Northern Illinois University biological sciences professor Richard King and his former student Eric Hileman examine the life history of the Eastern Massasauga, revealing important local climate impacts on the snake that should be carefully weighed when developing conservation strategies.

"Our results provide evidence that climatic variation in the Great Lakes region strongly influences body size, individual growth rates and key aspects of reproduction," says Hileman, first author of the study published in PLOS ONE, a journal of the Public Library of Science. Hileman earned his Ph.D. in biological sciences from NIU in December and is now a postdoctoral fellow in biology at Trent University in Ontario, Canada

Hileman, King and more than 40 co-authors gathered and synthesized more than a century of data on the snakes from study sites across the range of the Eastern Massasauga. Most of the data was culled from studies conducted from the mid-1990s forward at sites in Illinois, Indiana, Wisconsin, Michigan, Iowa, Ohio, Pennsylvania and New York,as well as Ontario, Canada.

The scientists found strong evidence for geographic variation in six of nine life-history variables. Among the findings:

The average body size of the snake and the size of its offspring increased with increasing mean annual
precipitation, possibly because wetter climates yield greater prey abundance.

Litter sizes decreased with increasing mean temperature, and increased by one offspring for each 1.89-degree increase in latitude, even when maternal size was held constant.

"It's been rare to look within a species and show that these patterns exist," King says. "The study results demonstrate that a one-size-fits all conservation strategy is not appropriate. Rather, assessments of extinction risk and the design of management strategies need to account for geography." 

"You're not likely to encounter them unless you're looking for them," King says. "It's easy to walk right by one. They're very cryptically colored to look like dead leaves and cattails, so they blend in exceedingly well."

The reptiles suffered habitat loss from extensive drainage of land for agriculture and development. As recently as the 1970s, some states had bounties on the snake.

Range of the Eastern Massasauga Rattler

With concerns over whether they would persist in the wild, the remaining snakes in Chicago's Cook County were taken into a captive breeding program in 2010, King says.

"In Illinois, they've nearly blinked out entirely," he adds. "We're probably down to one location in the southern part of the state that has a stable population. They seem to have stronger holds in Michigan and southern Ontario."

"The life-history parameter estimates will be essential for improving models related to extinction risk and climate change," Hileman says. "The results from these predictive models can subsequently be used to develop site-specific management strategies."

Habitat: Massasaugas live in wet areas including wet prairies, marshes and low areas along rivers and lakes. In many areas massasaugas also use adjacent uplands during part of the year. They often hibernate in crayfish burrows but may also be found under logs and tree roots or in small mammal burrows. Unlike other rattlesnakes, massasaugas hibernate alone. 

Reproduction: Like all rattlesnakes, massasaugas bear live young. Depending on their health, adult females may bear young every year or every other year. When food is especially scarce they may only have young every three years. Most massasaugas mate in late summer, and give birth about a year later. Litter size varies from 5 to 20 young. 

Feeding Habits: Massasaugas eat small rodents such as mice and voles but they sometimes eat frogs and other snakes. They hunt by sitting and waiting. Heat sensitive pits near the snakes’ eyes alert the snake to the presence of prey. They can find their prey by sight, by feeling vibrations, by sensing heat given off by their prey, and by detecting chemicals given off by the animal (like odors).

Range: Eastern massasaugas live in an area that extends from central New York and southern Ontario to southcentral Illinois and eastern Iowa. Historically, the snake’s range covered this same area, but within this large area the number of populations and numbers of snakes within populations have steadily shrunk. Generally, only small, isolated populations remain. The eastern massasauga is listed as endangered, threatened, or a species of concern in every state and province where it is found.

----------------------------------------------

Read more at: https://phys.org/news/2017-02-life-history-imperiled-rattlesnake.html#jCp

More information: Eric T. Hileman et al, Climatic and geographic predictors of life history variation in Eastern Massasauga (Sistrurus catenatus): A range-wide synthesis, PLOS ONE (2017). DOI: 10.1371/journal.pone.0172011 

Journal reference: PLoS ONE  

Provided by: Northern Illinois University