Marmoset. Credit: BUAV
"The monkeys could be seen crying out, twisting frantically, retching or desperately trying to escape"









Marmosets. Credit: BUAV





"All the experimental monkeys would be killed by injection, their tiny bodies dissected and their brains cut out and placed in jars"


The Cutting Edge

For 10 gruelling months, an investigator from the British Union for the Abolition of Vivisection (BUAV) worked undercover inside what claims to be one of the UK's leading academic brain research centres, Cambridge University.

Day after day, she secretly filmed and recorded the miserable fate of hundreds of marmoset monkeys imprisoned inside small, barren cages for their entire lives and deliberately brain-damaged for a mixture of basic research (curiosity-driven and aimed at simply 'finding out about' the brain) and applied research (trying to develop a marmoset 'model' of human illness such as Alzheimer's stroke and Parkinson's disease).

[Full report, PDF format]

The marmoset's natural habitats are the jungles, swamp forests and tree plantations of Brazil. At Cambridge University the marmosets were cruelly deprived of the space, social contact, enrichment, diet and complex environment essential to satisfy their biological, psychological and behavioural needs. They were deprived of any natural light or any serious attempt to provide even a moderately enriched or stimulating environment. Some monkeys were even caged on their own.

In the weeks before brain damage, monkeys were trained to perform behavioural and cognitive tasks. After brain surgery, these poor monkeys were made to repeat the tasks again, to see how far the brain damage had affected their ability to perform them. Water deprivation and/or food restrictions were often used to coerce monkeys to obey. That meant depriving the animals of water for 22 out of every 24 hours, with intermittent respite, for up to the entire length of the experiment. One test (for Parkinson's disease) involved shutting monkeys in a tiny Perspex box for up to one hour at a time to see how often they would rotate (an effect of the brain damage); injections of amphetamine or an apomorphine made them rotate faster or in the opposite direction. The monkeys were often clearly distressed and bewildered; they could be seen crying out, twisting frantically, retching or desperately trying to escape.

All the experiments included the deliberate infliction of brain damage (once, twice or even three times) by cutting or sucking out parts of the brain or by injecting toxins. A typical surgery involved placing the monkey under anaesthetic, holding the head in a stereotaxic device (which clamps the head firmly at the tongue, eyes and ears), cutting open the scalp, scraping away the muscle layer attached to the skull and then cutting drilling open the skull with an electric saw in order to inflict brain damage. One of the researchers callously described this as 'like taking a lid off'.

The immediate post-operative effects of the brain surgery included pain, distress, bleeding from head wounds, fits, vomiting, tremors, swelling and bruising, loss in body temperature, failure to eat and drink, abnormal body movements such as head twisting and body rotation, the loss of use in one arm or the whole side of their body, loss of balance and visual disturbances.

Long-term effects included physical disabilities, learning and memory impairment, weight loss and lack of self-care. Many monkeys appeared confused with blank expressions on their faces, their bodies uncoordinated. One monkey's confused state was described by a researcher as 'watching the birdies'.

At the end of their ordeal, all the experimental monkeys would be killed by injection, their tiny bodies dissected and their brains cut out and placed in jars. Their mutilated bodies were stored in the laboratory freezer before being disposed of like laboratory waste.

Remarkably, despite the obvious severity of the procedures these monkeys had endured during their short lives, the Government classified the experiments under the category of causing only 'moderate' suffering.


Humane alternatives >>

For more information about the investigation, see BUAV's Cutting Edge website at