Mutilated Monkeys Forced to Lift Weights

Posted by on July 1, 2020 | Permalink

A new study reveals that Newcastle University experimenters put monkeys under gruelling physical strain then killed and dissected them.

Image shows monkey in lab.

Please note the monkey and the device pictured are representative of what was used on the monkeys at Newcastle University.


The experimenters subjected two female rhesus macaque monkeys – known as Monkey L and Monkey N – to “strength training” for up to 13 weeks. Five days a week, the animals were made to perform 50 repetitions of pulling a load weighing up to 6.5 kilograms – in trials lasting around 20 minutes. They only weighed approximately 6 to 6.5 kilograms themselves, so when they were forced to pull the heaviest weights, this was equivalent to completing 50 one-arm pull-ups in 20 minutes.

Then, they were used for three more months of “strength training”, all in an attempt to show what impact weightlifting may have on the human brain.


Image is illustration of cruel weightlifting experimentJ. Neurosci 2020; 10.1523/JNEUROSCI.1923-19.2020

This only scrapes the surface of the kinds of abuse these monkeys were subjected to. Both also underwent multiple invasive surgeries:

  • Headpieces were fixed to their skulls using bolts to keep them from moving their heads during the strength-training tasks.
  • Electrodes were implanted in a muscle in between their thumbs and index fingers, in three different forearm muscles, and in the biceps, triceps, chest, and shoulder muscles. The electrodes were sewn onto the muscles and the wires tunnelled under the skin to connectors on the headpiece.
  • Parts of their skulls were temporarily removed to expose their brains so that a further six electrodes could be implanted.
  • Yet another electrode was implanted in Monkey L’s brain to stimulate the reward centre so that the experimenters could electrically manipulate her brain to send signals that may have resulted in feelings akin to pleasure. This was used during the “strength training” to keep her motivated.

At the end of miserable lives spent inside a laboratory far away from their forest home, these two monkeys were killed and dissected. They never knew what it’s like to swing from tree to tree with their loved ones, form relationships with their troop, or forage for food. They lived and died in captivity.

They weren’t the first of our fellow primates to be subjected to relentless cruelty at the hands of experimenters, and they won’t be the last – unless we take action.

What You Can Do

In 2018 alone, 3,207 procedures using primates took place in Great Britain. It’s time to relegate these cruel experiments, in which animals may be shaved, tattooed, placed in restraint cages, infected with debilitating diseases, or surgically mutilated, to the history books. We must shift away from all procedures using animals. Sign our petition to support PETA’s Research Modernisation Deal.