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Lincoln Park Zoo Aims to Save Chicago's Rattlesnakes

By Justin Breen | December 4, 2012 6:31am

LINCOLN PARK — High prices on the black market for pets and a vanishing habitat may have wiped out the local population of the Eastern Massasauga rattlesnake, Chicago’s only venomous snake.

There have been no documented reports of the small, reclusive rattler in Cook County since 2009, but researchers at Lincoln Park Zoo are trying to change that.

Joanne Earnhardt, a conservation biologist at Lincoln Park Zoo, was part of a team that extracted a male and female massasauga from a top-secret location three years ago.

“Don’t worry, it wasn’t in Lakeview,” Earnhardt said.

Earnhardt serves as coordinator of the Eastern Massasauga Rattlesnake Species Survival Plan, which aims to breed the ultra-rare snake and eventually to release it in Northeastern Illinois, including Cook County.

No official numbers exist, but the rattlesnake is listed as endangered in Illinois and has a current area population that’s “extremely low,” said Mike Redmer of the U.S. Fish and Wildlife Service, and the lead national biologist for the Eastern Massasauga.

“There’s a chance that some are still out there [in the Chicago area], but they have a very high value in the black market and could go for well over $1,000,” Redmer said.

Massasauga adults have an average length of about two feet. They are gray or light brown with large, light-edged chocolate brown blotches on the back and smaller blotches on the side, according to U.S. Fish and Wildlife Service’s website.

Earnhardt and Redmer said massasaugas are different than many rattlesnakes because they rarely use their rattle as a warning and sometimes don’t inject venom when they bite. Redmer, who said he has had more than 100 encounters with wild massasaugas, said they almost certainly won’t attack unless “you’re poking at them or step on them.” They ambush small rodents such as mice and voles, and sometimes frogs and other snakes.

Reintroducing them in Cook County has many hurdles, including finding the right habitat. Massasaugas require a wet, marshy environment that includes crayfish burrows in which to hibernate, and upland habitat for females to bask in the sun when they’re ready to give birth.

Plus, rattlesnakes aren’t exactly high on a anyone’s list of endearing animals.

“Getting people to care about conservation for a snake is not an easy thing,” Earnhardt said.

The captured female gave birth to four babies at the zoo in 2009. Three of them have been paired with potential breeding partners, but none have spawned offspring. The zoo has 11 massasaugas — four females and seven males — including one on exhibit that was born at the Detroit Zoo and 10 others behind the scenes as part of the breeding program.

Earnhardt said zoo personnel are conducting several studies to determine the best breeding conditions, while causing the least amount of stress to the reptiles. If the breeding program is successful, the snakes will be shipped to other zoos — there currently are 22 participating nationally with 53 total rattlers. Eventually, it's possible for some of the snakes could be released in Cook County.

“That is what we’re all working toward,” Redmer said. “They were here when the area was settled. I just find it interesting that they hung on in a very urban area for a long time.”