Route the Capuchin monkey had apparently picked up a zoo's cell phone to make the emergency call, say officials in western California state investigating call source.
A 911 call has forced California police officials to rush to a zoo only to find it had been placed by a mischievous monkey.
Dispatchers sent officers to investigate a possible emergency after receiving a call on Saturday night that had disconnected, officials said on Tuesday.
Sheriff's deputies in San Luis Obispo County traced the call to the offices of Zoo to You, a conservation park 320 kilometres north of Los Angeles, but couldn't find any humans in trouble.
Undeterred, and determined to get to the bottom of the mystery, they began to investigate.
"Then they all realised... it must have been Route the Capuchin monkey," said a social media post by the sheriff's office.
"Apparently, Route had picked up the zoo's cell phone... which was in the zoo's golf cart... which is used to travel around the zoo's 40-acre site."
Capuchins are particularly inquisitive creatures, who enjoy poking and pressing objects they pick up.
"And that's what Route did... just so happened it was in the right combination of numbers to call us."