By Ingrid Taylor, D.V.M.

In my opinion, the monkeys in Elisabeth Murray’s National Institutes of Health laboratory experience unrelenting isolation, psychological torment, and physical pain and discomfort. They are put under anesthesia and fitted with head chambers that allow the experimenters direct access to their brains. In these surgeries, experimenters cut through the skin and muscles of the scalp, and the head muscles are either retracted back from the skull or removed entirely. A headcap is screwed onto the skull, creating a chamber that allows access to the brain, but additional surgeries are required to remove bone from the skull and expose the brain. Other monkeys are subjected to injections that destroy the functions of certain areas of their brains. Murray has also used suction to remove certain parts of their brain. Because there are many nerve endings in the skin and muscle of the head, these surgeries cause high levels of immediate pain but may also cause chronic or longer-lasting pain. Monkeys who have undergone brain surgery likely experience headaches and pulsing or pounding head pain, similar to what humans describe after brain surgery. One-third of humans who’ve undergone brain surgery report experiencing headaches for long periods of time after their surgeries. Although the monkeys reportedly receive pain medications for up to seven days after the surgeries, their pain may last much longer.

During the course of the experiments, individual monkeys undergo as many as three invasive surgeries and possibly more if there are any complications, adverse effects, or bone regrowth into the head chamber. In addition to chronic pain, the side effects of repeated surgeries and anesthesia include stress on internal organs such as the kidneys and liver, memory loss and cognitive decline, and immune system suppression, leading to a higher risk of infection and illness. The permanent attachment of the head chamber likely causes additional distress and may lead to sleep disruptions, inability to move or rest comfortably, and anxiety from the constant presence of a foreign object on the head.

Monkeys are subjected to repeated painful injections into the muscles of their legs and arms, which can cause bruising, swelling, and a decrease in the ability to move and rest pain-free. Potential side effects of the drugs some of the monkeys receive include itching, redness, uncontrolled muscle twitching, agitation, sedation, blurred vision, and hearing impairment. The monkeys are held in restraints repeatedly to administer injections and experimental drugs.

These monkeys, who are intensely social and rely on the community of other monkeys for their well-being, are housed alone in metal cages, unable to touch or interact with others of their own species. Monkeys who are isolated experience anxiety, frustration, and mental distress, and they often express this anguish through physical ailments and repetitive behaviors such as pacing, rocking, twisting their heads back and forth, plucking out their own fur, eating their fur, poking at their eyes over and over again, sucking on their fingers, or biting and scratching their own arms and legs to the point of serious injury. Monkeys are sentient beings who experience joy, grief, fear, sadness, and loneliness. There is no justification, scientifically or ethically, for these cruel experiments.

Ingrid Taylor is a veterinarian with PETA’s Laboratory Investigations Department.