Aransas Pass Officer Keith Moore wrote out a speeding ticket. As he was handing the ticket to the driver, a pet monkey jumped from the back seat and bit the officer's right hand.
Moore had a miniature video camera on his glasses which captured the incident.
"We're taught to be on guard at all times, but at that point I wasn't on guard for a monkey," said Moore.
The monkey got a warning but no ticket. The bite left a mark, but the 21-year-old officer was not hurt otherwise.
The trained monkey makes appearances at carnivals and other entertainment events.
The Associated Press contributed to this report.