Holiday market shoppers in Cambridge and downtown will get a sonic shake-up on Thursday when PETA displays a mobile billboard blasting an audio recording of crying, distressed infant monkeys who have been separated from their mothers. The ad—rejected by Boston TV stations—is the latest in a PETA campaign protesting Harvard University experimenter Margaret Livingstone’s terrifying maternal and sensory deprivation experiments on monkeys.

PETA’s mobile billboard will circle around the Harvard Square Holiday Fair (1 Brattle Square), Snowflake Crossing (Downtown Crossing), the Boston Women’s Market (Faneuil Hall), and Snowport (100 Seaport Blvd.).

“Livingstone’s pointless experiments terrorize baby monkeys, who are stolen from their mothers and deprived of any face-to-face contact,” says PETA neuroscientist Dr. Katherine Roe. “PETA asks that shoppers extend the holiday spirit to these infant monkeys by calling on the university to end these twisted experiments.”

Livingstone has ripped baby monkeys away from their mothers and sewn the infants’ eyes shut for up to a year, just to see how abnormally their vision develops. In other tests, the baby monkeys are reared by humans wearing welding masks so the traumatized animals never see a monkey or a human face. She then immobilizes their heads using head posts, chin straps, and bite bars to test their facial-processing abilities or surgically implants electrodes in their brains to record how their deprived brain cells respond to visual stimuli. After years of torment, she kills many of the monkeys and dissects their brains. She has conducted these types of curiosity-driven experiments for 40 years without identifying a treatment or a cure for humans.

PETA first exposed Livingstone’s depraved experiments. Since then, nearly 400 scientists—including primatologist Jane Goodall, conservationist Ian Redmond, and Harvard’s Dr. Richard Wrangham—have joined the call to shut down her shop of horrors.

PETA—whose motto reads, in part, that “animals are not ours to experiment on”—opposes speciesism, a human-supremacist worldview. For more information on PETA’s investigative newsgathering and reporting, please visit PETA.org, listen to The PETA Podcast, or follow the group on X, Facebook, or Instagram.