THE STORY – An investigation reveals a hidden world of pain in laboratory research, highlighting Dr. Lisa Jones Engel’s journey questioning the justification of harming animals and humans for science.
THE CAST – N/A
THE TEAM – Tony Jones (Director/Writer) & Rachel Grierson-Johns (Writer)
THE RUNNING TIME – 105 Minutes
“I’ve always liked Roger Ebert’s idea that films are like a machine for generating empathy,” Director Tony Jones states. “It’s an idea at the core of what I want our documentary to achieve—empathy, first of all, for the caged animals but also for animal carers and the scientists and researchers who experiment on those animals.” In “Sentient,” co-written by Jones and Rachel Grierson-Johns, this machine is fueled by a blend of grief and clinical inquiry. The film opens with a sound that bypasses the intellect to strike the marrow: the high-pitched crying of monkeys packed into tiny cages in the back of a truck. It is a calculated, bruising start that signals this will not be an easy viewing experience. Instead, it is an invitation to witness a hidden ecosystem where the trauma of the captive is inextricably linked to the moral injury of the captor.
Early on in the documentary, a voice asks, “Do we have a right to use them in this way?” Another voice answers, “I’m thoroughly convinced that we do not have the right. I can only say that we have a need.” “Sentient” moves beyond the binary of “right versus wrong” to investigate the more claustrophobic space of “need versus right.” Nowhere is this dissonance more striking than in the footage of the Washington National Primate Research Center. Above ground, cherry blossoms drift across a serene university quad; beneath the students’ feet, primates pace in sterile isolation. Dr. Sally Thompson-Iritani, who oversees these monkeys, provides one of the film’s most vulnerable moments when she breaks down describing a time early in her career when she found a monkey dead and alone in its cage. It is a haunting admission of the psychological cost of “care” within a system where the researchers constantly question whether they are really doing the right thing.
The film expertly navigates these conflicting layers, refusing to paint the scientific community as a monolith of indifference. Instead, it portrays them as individuals caught in a historical momentum they feel powerless to stop, even as their own souls are taxed by the work. At the center of this moral labyrinth is Dr. Lisa Jones-Engel, a primatologist whose trajectory from researcher to advocate provides the film’s narrative spine. Her early work in Borneo, captured in old footage and images, establishes a profound connection to these creatures—beings she describes as “just another version of me.” This early reverence makes her later work at NYU’s LEMSIP (Laboratory for Experimental Medicine and Surgery in Primates) lab feel even heavier.
While it was a lab environment, LEMSIP feels like a stark contrast to even a modern space like the Washington National Primate Research Center. LEMSIP’s director, Dr. James Mahoney, had two rules: the science had to be impeccable, and the welfare of the animals had to be off the charts. But despite this, a darker tone comes into play as Jones-Engel explains how they had to take the baby chimps away from their mothers. You see how the work can be fulfilling as she cares for and bonds with these chimps, but as she acknowledges, becoming a mother made her realize the pain she caused her primate counterparts.
The documentary uses her perspective, alongside that of her colleague, Dr. Douglas Cohn, to show what really drives people to this work. In Cohn’s case, as a gay man in the 1980s, his research was fueled by desperation for a cure for HIV after watching friends die, creating a tragic hierarchy of survival where the sacrifice of the chimp is often framed as the only path to human salvation. Yet, the film masterfully pivots to the systemic failure of this logic, citing Dr. Aysha Akhtar’s startling data: 95% of vaccines deemed successful in animal trials fail when they reach humans. This revelation shifts the film from a study of ethics to a critique of a flawed scientific ritual that may be more about tradition than progress.
As “Sentient” nears its conclusion, it delivers a narrative twist that reframes animal testing as a public health liability. The capturing of wild long-tailed macaques to supplement breeding farms has pushed the species toward extinction while simultaneously introducing unknown pathogens into the research pipeline. The industry, we are told, is perhaps more likely to ignite a pandemic than to prevent one. This systemic oversight serves as a grim metaphor for the broader human condition: our tendency to exploit the natural world so aggressively that we inadvertently architect our own downfall.
“Sentient” succeeds because it refuses to take sides, looking at both those who believe in this biomedical research and those who have suffered greatly from it. It is a vital, torturous exploration of the truth that exposes the heavy toll extracted from both the caged and the keepers. The film leaves us with the hollow gazes of former workers who now live in the quiet wake of their regret, grappling with guilt that no medical breakthrough can cure. In asking whether our perceived need for these experiments justifies the erasure of another being’s autonomy, Jones doesn’t just critique a laboratory practice; he demands a reckoning within the very definition of human progress and an acknowledgment that there is no difference between us and the primates encaged.
