Footage documents maternal separation in University of Washington study

Researchers separated 28 infants after dosing 32 pregnant macaques

The Guardian reported that video footage released by the animal-rights group Peta revealed, for the first time, filmed experiments at the University of Washington’s National Primate Research Center. Records show that infant macaques were separated from their mothers and subjected to neurological tests after prenatal exposure to domoic acid, a neurotoxin produced by marine algae that accumulates in shellfish and can cause illness in humans. The Guardian described the domoic-acid work as a six-year project that ran from 2014 to 2020; some infant monkeys were just two days old.

The video shows monkeys with electrodes attached to their heads as researchers shave their heads and test their reflexes and memory. The babies appear distressed as they clutch blankets, suck their fingers, screech and jerk during the procedures. The tests were intended to determine whether exposure to domoic acid in the womb had damaged their brains.

The infant macaques were bred at the University of Washington’s Infant Primate Research Laboratory for research on the developmental neurotoxicity of domoic acid in nonhuman primates. Researchers administered doses of domoic acid daily to 32 pregnant macaques. After birth, 28 infants were removed from their mothers, bottle-fed and kept in incubators before being housed individually at three weeks old. The project received more than $4.2 million in National Institutes of Health funding, and some experiments lasted years. According to Peta, the monkeys were killed after the experiments concluded.

Dr Malene Hansen, a long-tailed macaque expert, said macaques in the wild live in close social groups and that infants have long-term maternal-care needs for their social and behavioral development. She said infants cannot thrive without their mothers. “It is unethical to conduct research that separates infant macaques from their mothers. Period,” Hansen said.

The National Primate Research Center told the Guardian: “We recognize that research involving infant animals raises important questions about their wellbeing. Maternal relationships and early social development are important considerations in nonhuman primate welfare. Our experienced veterinary and animal care personnel have specialized expertise in primate care, including nursery rearing.” The National Institutes of Health separately said: “All animals used in NIH-supported research are protected by laws, regulations and policies designed to ensure the smallest possible number of animals are used and their welfare is prioritized.”

Peta’s chief science adviser on primate issues, Dr Lisa Jones-Engel, said: “These monkeys are so young they still have the distinctive black fur of newborn macaques, yet instead of clinging to their mothers, they grasp blankets on metal tables.” She also said: “There is no moral escape hatch. You can’t claim primates are used because they’re so like us, then take an infant away from its mother and experiment on it. You would never do that to a human primate. The cruelty also has biological consequences: maternal separation alters an infant’s physiology, immunity, behavior and development, distorting its response to the very substance or disease being studied.”

The Guardian described Jones-Engel as one of the University of Washington’s most outspoken critics. Jones-Engel said the footage offered a rare glimpse into experiments involving monkeys: “For decades, the term ‘primate research’ has obscured the reality inside laboratories. These videos expose the suffering and raise a fundamental question: why are these facilities still operating at all?” The Guardian reported that she worked as a primate scientist at the university for 17 years and has spent 35 years working as a primatologist. Her transition from animal researcher to campaigner is documented in a new film, Sentient. Peta is calling for the closure of all seven US National Primate Research Centers.

According to the National Primate Research Center, the studies contributed to understanding how prenatal domoic acid exposure may affect learning and memory. The center said, “These findings remain relevant to public health.” The Guardian reported, however, that there was no clear evidence that the experiments led to changes in public-health recommendations. The center also said no infant studies were currently taking place, although protocols for such studies remained active.

The footage relates to a research program that has operated at the University of Washington’s Infant Primate Research Laboratory since 1971 and emerges amid a long-running dispute between Peta and the university. In a 2020 lawsuit, Peta challenged the school’s handling of public-records requests. The court ruled that the university violated laws by failing to search adequately for records, in a case that revealed systematic destruction of photos and videos at the school. The videos were filmed between 2017 and 2019 and released to Peta in September 2026 in response to a records request.

Although the domoic-acid research ended in 2020, records show that the center continued to breed, purchase and use monkeys, including infants, to study viruses such as Epstein-Barr and HIV. In a 2021 study, 25 infant rhesus macaques were infected with SIV, which is closely related to HIV. The study was looking at why some infants develop AIDS more rapidly than others. The infected baby monkeys experienced significant distress, chronic diarrhea and body wasting before they were killed for autopsy.

In another study, 10 infant monkeys were separated from their mothers within two days of birth to test an experimental Epstein-Barr vaccine.

Supporters of primate research argue that biological similarities between humans and nonhuman primates make monkeys useful for studying human disease. The Guardian reported that decades of animal research have yet to produce an approved HIV vaccine.

Research scientist Dr Jarrod Bailey argues that biological differences mean monkey experiments often fail to deliver treatments for human diseases, including HIV/AIDS, Alzheimer’s and Parkinson’s. “We pay the price in failed treatments; monkeys pay with their lives. A shift away from monkey experiments would benefit all primates – including humans,” Bailey said.

The University of Washington said it was committed to replacing, reducing and refining animal experiments through emerging technologies and improved animal care, but said “animal studies remain necessary for some complex scientific questions.” Federal agencies in the United States are shifting toward reducing animal testing in favor of new approach methodologies, including organ-on-a-chip technology and computer modeling, and the NIH is investing in human-based alternatives. Primate research nevertheless remains widespread: more than 106,000 monkeys were held in US facilities in 2025, up 1.5% from 2024, and more than 32,000 primates were imported from Asia and Africa for laboratory use from 2025 to 2026.