Skip to main content

Animal 22

Animal 22

Through 2020, Elon Musk’s company Neuralink paid $1.4 million to the University of California, Davis, to use its facilities, where experimenters removed portions of monkeys’ skulls to implant electrodes in the animals’ brains related to the development of a “brain-machine interface.” Only in 2022, following a public records lawsuit by the Physicians Committee for Responsible Medicine, did the troubling details of these experiments begin to come to light. The company is still conducting experiments on animals at its facilities in California and Texas.

This is the story of one monkey, “Animal 22.” He was a male macaque who was 6 years old when he was transferred to the Neuralink experiment. In September 2018, staff noted that he had “patchy alopecia on both legs.” This would persist for more than a year.




For nonhuman primates in labs, studies show that hair loss is often due to poor psychological well-being and/or underlying medical issues. 

On Jan. 21, 2020, during a 7-hour surgery, a Neuralink employee cut open the skin and muscle atop Animal 22’s head, drilled two holes in his skull, implanted electrodes in his brain, attached two “pill boxes” to his skull using bone screws, and inserted a port under his skin. 




One week later, UC Davis staff noted that “there is a ‘crepitus like’ sensation” near the port, meaning a crackling or popping sound that occurs as a result of tissues rubbing together abnormally. When they removed the collar around the port a “large volume of bloody fluid was expressed.” 




On Feb. 12, staff noted “dried blood” around the implant and believe Animal 22 had been “picking” at it.




On March 26, the implant, which was screwed into Animal 22’s skull, was “loose today.” 




Later that day, staff noted that the implant moved when “minimal pressure” was applied. They decided to euthanize Animal 22. 




The necropsy report for Animal 22 noted that two screws “attaching the implant to the skull were loose and could easily be lifted out” and “the implant could be easily pivoted…” 




The necropsy report later stated that the “failure of this implant” was “purely mechanical.”