Two American nationals were arrested in Japan after a stunt in which one entered the monkey enclosure at a zoo where a baby macaque named Punch became a global internet sensation this year, police said Monday.

One of the men, who identified himself as a 24-year-old college student, was arrested Sunday after climbing over a fence and dropping into a dry moat surrounding the monkey exhibit at Ichikawa City Zoo in Chiba Prefecture.

The other man, who was filming the act, identified himself as a 27-year-old singer.