As Alicia Beattie released mudpuppy No. 29 from her blue plastic gloves back into Wolf Lake, she said: ‘‘Pretty exciting to be finding them here, right next to the road. Wolf Lake is a cool place. People are driving by at 70 mph [on I-90 to the east].’’

Beattie, a Southern Illinois graduate student, is working on a study of mudpuppies in the Chicago area with help from Philip Willink, a senior research biologist at the Shedd Aquarium.

There’s a stunning lack of knowledge about mudpuppies, those large, totally aquatic salamanders. They vary greatly in color and are a unique salamander for having four toes on each foot.

Willink calls them ‘‘the mystery species.’’ Beattie wants the mystery passed to future generations, saying: ‘‘The wonder of having a species like this is pretty cool.’’

There’s a practical side to finding mudpuppies.

‘‘They have really sensitive skin, so they are really sensitive to pollution,’’ Beattie said. ‘‘So to find them in Wolf Lake is a good sign.’’

On Wednesday, she and friends checked traps near the flagpole at William W. Powers State Recreation Area on the Southeast Side. A fisherman told her — correctly — that was a prime spot for mudpuppies, which are listed as threatened in Illinois.

The holes are drilled with a 10-inch power auger. The ice was 27 centimeters (101/2 inches) thick. She needed large holes to fit in wire minnow traps, which were held on the bottom by a homemade weight: a plastic cup filled with cement with an I-bolt.

The traps are baited with live minnows and minnow parts in a mesh bag. The mesh bag is important so the mudpuppies don’t eat the minnows because Beattie ‘‘burps’’ them to regurgitate their stomach contents.

She implants a PIT tag in the tail of each mudpuppy and notes each’s vitals and the GPS of capture location. She is establishing a base for future studies. So far, she has recaptured two mudpuppies, as noted through the PIT tag.

From stomach contents, she found they are eating the invasive round gobies on Lake Michigan, other fish parts, crayfish claws, small aquatic insects and snails, the basics of aquatic carnivores.

‘‘It is pretty diverse,’’ Beattie said. ‘‘They are not real selective in what they eat.’’

The start to her study was truly hit-and-miss. She found her first mudpuppy June 2, stuck in two rocks in Monroe Harbor. She didn’t find her second one until Oct. 25.

‘‘I was really trying, too,’’ Beattie said.

Then in the fall she found three while flipping rocks on the lakefront. Her traps on Lake Michigan were made difficult because of the wave action and its impact on paddling around with dozens of traps.

Mudpuppies have a mixed history. At one point, they were used as specimens for college and high school students to dissect. Fishermen used to use them as bait.

With their odd look — their external gills look like a string of beads a flamboyant parader would wear at Mardi Gras — the public thought they were poisonous.

‘‘They are really harmless,’’ Beattie said. ‘‘They are fascinating creatures. It is really cool to have them right here in Chicagoland.’’