A fence encircles the human colony on Lusitania, separating the humans from the pequeninos. Only xenologers and their apprentices are allowed to cross the fence, and when they do, their interactions with the pequeninos are limited by the Starways Congress’s stringent rules. The fence stimulates pain receptors and causes intense pain to any body parts that enter its field. The pequeninos chew capim grass which has anesthetic properties and allows them to regularly climb the fence and spy on the humans. Miro attempts to chew the grass and cross the fence, but it does not work, and he experiences extreme pain that causes permanent and disabling brain damage.

The fence appears repeatedly in the story, and is representative of interspecies relationships and The Importance of Cross-Cultural Empathy. It symbolizes the vulnerability required to bridge cultural gaps. Different characters perceive the fence in different ways. Bosquinha and many of the residents view the fence as a symbol of safety; they hate the pequeninos and believe that the fence effectively keeps the pequeninos away. This mindset is proven ironic when the pequeninos reveal they have been crossing the fence for years. The fence also symbolizes cultural differences, and