YouTube has restored some videos of robots fighting after wrongly removing hundreds for displaying a “deliberate infliction of animal suffering or the forcing of animals to fight”.
Sarah Pohorecky, of Massachusetts Institute of Technology, said film of her robot So Rachet removed on Monday “mysteriously reappeared” on Tuesday.
YouTube has acknowledged the error.
A spokeswoman said: “With the massive volume of videos on our site, sometimes we make the wrong call.”
She added it would work quickly to reinstate the other videos.
Jamison Go, a research assistant at MIT, said he had lost nine videos but others had lost hundreds.
“Today is a sad day,” he said on Monday in a Facebook post.
“Robot builders across the world cried out in agony as YouTube’s algorithm falsely identified personal videos of robot sport as ‘animal cruelty’ and ‘cock fighting’.”