I suppose the only reason you’d want to catch a monkey would be to eat it, no? AP:

To prepare for the show, the 67-year-old Johnson built a shelter, started fires from scratch and tried to get physically fit. Once in Nicaragua, his experience as a Keys fisherman helped, but food was still hard to come by.
“It’s a beautiful country, but it’s a very harsh environment,” Johnson said. “There was a lack of fruit. There was some fish. We had some interaction with howler monkeys, but we couldn’t catch them.