Hellboy Star Ron Perlman Wants University of Minnesota, His Alma Mater, to End Monkey Brain Tests, Bar Experimenters

For Immediate Release:
September 28, 2026

Contact:
Sydney Rader 202-483-7382

Today, Ron Perlman sent a letter to University of Minnesota President Rebecca Cunningham, urging her to immediately end painful brain experiments on monkeys conducted by Jan Zimmermann and Matt Johnson, retire the surviving animals to sanctuaries, and bar these three experimenters from ever experimenting on animals again. In his letter, Perlman lauded the university for taking decisive action against a third experimenter—Geoffrey Ghose—and asked it to take similar action against Zimmermann and Johnson.

For years, Zimmermann, Ghose, and Johnson—none of whom are surgeons—have conducted curiosity-driven experiments in which they slice open monkeys’ scalps, remove part of the skull, affix headposts and cranial recording chambers, and implant electrodes into their brains. PETA has obtained records revealing that the monkeys repeatedly endure painful complications from failed implants, festering infections, and botched surgeries.

Perlman is incensed that Zimmermann drilled 20 screws so deeply into a monkey’s skull that they pierced his brain, causing him to vomit, weaken, and suffer for months before being killed; that Ghose left a monkey named Bilbo with his brain exposed for days after an implant chamber fell off following an infection; and that Ponyo, a monkey in Johnson’s laboratory, reportedly suffered an infection for weeks—with blood leaking from a screw hole—until her headpost detached from her skull while being restrained, presumably because the infection had weakened the bone.

“After everything these monkeys have endured, they deserve retirement—not another experiment,” writes Perlman, who received his master’s degree from the university in 1973. “I also respectfully ask that the university permanently prohibit these experimenters from conducting experiments on monkeys so that no other animals are subjected to the same suffering.”

A 2023 study by PETA scientists ranked the University of Minnesota the nation’s fifth-worst violator of federal animal welfare standards among schools with taxpayer-funded laboratories. In nature, macaques live in large, tight-knit groups, travel up to two miles each day exploring diverse habitats, and cuddle together in their favorite “sleeping trees” at night—a world away from what they endure in the University of Minnesota’s laboratories.

PETA—whose motto reads, in part, that “animals are not ours to experiment on”—points out that Every Animal Is Someone and offers free Empathy Kits for people who need a lesson in kindness. For more information, please visit PETA.org or follow PETA on X, Facebook, or Instagram.

Perlman’s letter to Cunningham follows.

To: Rebecca Cunningham

President

University of Minnesota

Morrill Hall, 2nd Floor

100 Church St SE

Minneapolis, MN

Dear President Cunningham,

I am writing to urge the University of Minnesota to retire the surviving monkeys from the laboratories of Jan Zimmermann and Matt Johnson to reputable sanctuaries where they can finally begin to recover from years of invasive experimentation. I was encouraged to learn that, following a formal letter of reprimand and the cancellation of his protocols, Geoff Ghose no longer experiments on monkeys. I respectfully ask the university to take similarly decisive action against Zimmermann and Johnson, end their experiments on monkeys, and ensure that no other monkeys are subjected to such suffering.

I have learned that, for years, these laboratories have subjected monkeys to invasive brain surgeries in which portions of their skulls are removed, metal devices are implanted into their heads, and electrodes are inserted into their brains. According to records obtained by PETA, these laboratories have experienced repeated surgical complications, infections, device failures, and other serious animal-welfare concerns, raising profound questions about oversight and accountability.

At a time when leading universities are increasingly embracing sophisticated human-based technologies—including organs-on-chips, organoids, advanced imaging, and artificial intelligence—that are more directly relevant to human biology, and when funding priorities at the National Institutes of Health and among private philanthropies increasingly reflect that shift, continuing to rely on invasive monkey experiments leaves the University of Minnesota increasingly out of step with the direction of state-of-the-art biomedical research.

Retiring the surviving monkeys to reputable sanctuaries would allow them to live out the rest of their lives in peace after enduring years of invasive procedures. After everything these monkeys have endured, they deserve retirement—not another experiment. Taking this step would also demonstrate compassionate leadership and help ensure that no other monkeys are subjected to similar suffering.

Thank you for your time and consideration. I respectfully urge you to act.

Sincerely,

Ron Perlman