People pens are very large fence enclosures that connect to the building. One would think they were for animals but actually they are for "people" in case the building needs to be evacuated. I guess people couldn't just exit out to the savannahs with the animals! Some people are not concerned about them, but my family did not particularly care for them. I am positve now that I think about it that the Arusha Savannah did not have them.