"Marius Monaghan made a last-minute decision to visit Belfast Zoo on February 9 and was greeted with a bunch of mischievous chimps.
Having placed a tree trunk next to the enclosure wall, the chimps then climb up before jumping the rest of the distance and grabbing on with their hands.
Once they were perched on the top of the wall, the chimps then walked down the paths and mingled with guests."