Researchers and wildlife watchers are mourning the death of what may have been the most photographed bobcat in Tucson.

For more than five years, the cat known to many as Mama lounged and hunted at Sweetwater Wetlands, sometimes with her kittens in tow.

She would roam the grounds with apparent calm, while surprised human visitors trailed her, often with cameras in hand.

“We’re still grieving over the fact that Mama died,” said John Gentile, a naturalist who has been observing the bobcat at the wetlands since 2017. “She was an amazing, amazing cat.”

The mature female was found dead on Jan. 9 at Pima County’s shuttered wastewater treatment plant just north of the wetlands park.

County workers retrieved her body from inside a drain pipe at the bottom of an empty sewage tank at the site. She was still wearing the tracking collar that was placed on her in November, when biologists trapped her along the Santa Cruz River as part of the ongoing Bobcats in Tucson Research Project.

Her exact cause of death is unknown, but an examination of her remains revealed significant trauma to her head and left shoulder, said Kerry Baldwin, a retired Arizona Game and Fish Department biologist who now serves as project coordinator for the study.

The research team suspects the cat may have been hit by a car on a nearby road and left badly injured on Dec. 9 or 10, when telemetry data from her collar show an abrupt change in her behavior.

During the three weeks before that, Mama — or Cassidy, as researchers knew her — was tracked roaming widely through her home range, which included Sweetwater and the river corridor to the north of it.

But after Dec. 10, the cat stopped moving almost entirely and spent the next six days hunkered down within a 500-foot area of the old treatment plant, which shut down in 2013.

“This is not normal behavior,” said wildlife biologist Cheryl Mollohan, lead investigator for the research project. “I believe she was injured and incapacitated at this time.”

Down in the tank

The research team would later learn that on Dec. 15, a crew from the county spotted a collared bobcat in an empty waste processing tank at the site. The animal was seen walking in tight circles at the bottom of the tank, a behavior consistent with neurological trauma or possibly rabies, Baldwin said.

County workers contacted the Arizona Game and Fish Department and placed tree branches in the 20-foot-deep tank so the cat could climb out. The animal wasn’t seen again after Dec. 19, so workers assumed she had freed herself.

Instead, it appears the bobcat crawled inside one of the tank’s 10-inch-diameter drain pipes, where her collar was shielded from broadcasting her location, and died there.

Mollohan believes Cassidy’s injuries were so severe that she could not have been saved, but it upsets the scientist to think of the animal suffering alone at the bottom of the tank for several days.

“The county crew tried very hard to get her help and should be commended,” Mollohan said. “I am heartsick that we were not there to help her.”

Pima County Regional Wastewater Reclamation Director Jackson Jenkins said the 40-acre plant site is surrounded by industrial security fencing that is inspected regularly but “does not necessarily keep small animals out of the facility.”

Even so, he said, it is rare for wildlife to end up in the empty tanks there.

News of Mama’s death prompted an angry reaction from some photographers and other wetlands regulars, who were already upset to see the beloved cat wearing a tracking collar.

Steve Vaughn said he had been watching Mama at Sweetwater for the past seven years, and he insists her behavior changed after she was caught and collared.

In a letter to Mollohan after the cat was found dead, he said he holds the research team “responsible and accountable” for the stress they caused Mama by trapping and tranquilizing her and for making her last month of life “less comfortable” with a tracking device around her neck.

More than 600 people have signed an online petition calling for the study to be halted and the collars removed from the remaining cats still being tracked.

When the cage door opens, collared cats don't wait around.

Loss and legacy

The research team has tried to counter such criticism with transparency, freely sharing their methods and their findings with whomever asks.

Since November 2020, 49 different bobcats have been trapped and 31 have been fitted with tracking collars to study how the animals live in the desert neighborhoods on Tucson’s west side.

Cassidy was the 10th test subject to die. Three of the cats in the study were killed by vehicles, three were shot and three died of unknown causes, including one that was found dead within a day of being captured and released.

Mollohan said the tracking data, visual records and other measurements collected so far show no evidence that the bobcats are being hampered by the collars they are wearing.

When the cage door opens, collared cats don't wait around.

Four adult bobcats have been caught and collared twice over the course of the study, and all of them weighed more the second time around. Two of them successfully raised kittens while wearing their collars, Mollohan said.

Gentile considers the study well-run and necessary, but he said some critics will never be convinced of its safety or its value to Tucson’s bobcat population as a whole.

Bitter disagreement over the research has “fractured” a group of Sweetwater regulars that initially came together to develop guidelines for responsible wildlife viewing at the wetlands, he said.

“It got really ugly. There’s a lot of animosity there,” Gentile said. “It challenged a lot of friendships. It really did.”

Those divisions have only deepened since Mama’s death, a testament perhaps to how familiar and beloved the cat had become.

Gentile will certainly miss her.

Over the past five years, he has watched from a respectful distance as she hunted, climbed, bathed and played at Sweetwater Wetlands. He also got to see Mama raise at least four litters of kittens there.

“Her legacy still lives on,” he said.

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Contact reporter Henry Brean at hbrean@tucson.com or 573-4283. On Twitter: @RefriedBrean