Visitors described seeing one of the escapees emerge from the bushes on to a path while others were sitting on top of their enclosure wall.
Chimpanzees have used a branch to escape from their enclosure at Belfast zoo in the second breach by animals in recent weeks.
Chimpanzees escape from enclosure at Belfast Zoo using a branch as an improvised ladder:
'Different story' Footage posted on social media shows a chimpanzee on a path with members of the public, while several other chimpanzees remained on the enclosure wall.
Chimpanzees escape from Belfast Zoo enclosure using tree branch ladder
Considering this is the second time this year that a creature has escaped from the Belfast Zoo, we can only hope the animals are being treated better than they were in the 2011 reboot of the "Planet of the Apes" franchise, "Rise of the Planet of the Apes."
Chimpanzees, members of the "great apes" alongside gorillas and orangutans, are considered to be the second smartest primate on the planet.
Chimpanzees at Belfast Zoo create makeshift ladder to escape enclosure
“Zookeepers were present as the chimpanzee quickly returned from an adjacent wall to the rest of the group inside the enclosure,” it said.
Media playback is unsupported on your device Media captionOne of the chimps ventured a bit further than the others She said they "could not believe it" when the "smart" chimpanzees started to climb out of the enclosure, and when they went to take a closer look, they ended up "a foot" away from one of them.
These chimpanzees used branches brought down by Storm Erik to escape from their enclosure at Belfast Zoo - giving one family a closer-than-expected experience
Zookeepers say a group of chimpanzees used branches weakened by a storm to make a ladder and escape from their enclosure at the Belfast Zoo.
The Associated Press reports "Zookeeper Alyn Cairns said trees in the chimps’ enclosure had been weakened by recent storms, allowing the animals to break them and fashion a ladder to escape.
We have a real-life "Planet of the Apes" scenario in Northern Ireland as zookeepers say a troop of chimpanzees used fallen branches to construct a ladder for a daring escape last week.
Chimpanzees use branches to make ladder, escape from zoo
Moan the chimps... Chimpanzees have used a branch to escape from an enclosure at Belfast Zoo. They turned it into a makeshift ladder and scaled high walls surrounding their pen onto a path, shocking visitors.
Image copyright Chantal Baxter Image caption The zoo's Alan Cairns said the "intelligent" primates "got back in themselves" "They're intelligent primates and know they're not supposed to be out of their enclosure, so got back in themselves," he said.