A medical company founded by Elon Musk is under investigation for potential welfare violations — 1,500 animals died in four years, according to a report.
Neuralink staff have filed internal complaints that animal testing was rushed — causing unnecessary suffering and death, Reuters said.
Since 2018, 280 sheep, pigs and monkeys have died after the experiments, according to records seen by news organizations.
Read more: Elon Musk’s Neuralink puts computer chips in pig brains
Neuralink is developing a brain implant it hopes will help paralyzed people walk again — and cure other neurological problems.
Complaints from staff allege that Musk intensified the pressure to speed up development, leading to the need to repeat botched experiments.
In one reported case, 25 pigs were implanted with the wrong-sized device — a mistake that could have been avoided with more preparation, a source told Reuters.
Earlier this year, a Neuralink executive reportedly sent employees a news article about Swiss researchers developing an electronic implant that could help a person walk again.
He wrote: “Overall, we are not moving fast enough. This is driving me nuts!”
Reuters also said that Musk has repeatedly told employees to imagine a bomb strapped to their heads to make them move faster.
The total number of animal deaths does not necessarily indicate that Neuralink violated regulations or standard research practices.
Many companies routinely use animals in experiments to advance human healthcare, and they face financial pressure to get products to market quickly.
The animals are usually killed after the experiment is complete, usually so that they can be autopsied for research purposes.
But more animals died there than needed, current and former Neuralink employees said.
The San Francisco-based company has sought FDA approval for its Neuralink project, which has seen scientists develop a tiny implant with more than 3,000 electrodes attached to a single hair One-tenth the size of a flexible wire, and capable of monitoring about 1,000 neurons.
At launch, Mr Musk said they had three pigs, each with two coin-sized implants, which he described as “healthy, happy and indistinguishable from normal pigs”.
The alleged problems highlighted in the Neuralink tests have raised questions about the quality of the data generated by the experiments — which could delay attempts to start human trials.
But some employees interviewed by Reuters said the company’s treatment of animals was fairly good compared with other research institutions — animals roam free in what has been likened to “Disneyland for monkeys.”
A former Neuralink employee recalled that Musk said he didn’t like using animals for research, but wanted to make sure they were “the happiest animals” when they were alive.
Musk and other Neuralink executives did not respond to a Reuters request for comment.