Like in many ecohorror texts, one theme of Borne is ‘nature fights back’. However, there were no consequences until the Company experimented on humans. The biotech had existed long before the Company collapsed. At one point, Rachel reflects on memories from her childhood and how biotech had once been harmless; used for entertainment, decoration, and a sign of wealth. She recalls a restaurant where “little biotech creatures that looked like fluffy baby birds mixed with adorable hamsters gamboled and chittered and put on shows on the wide window frame” (VanderMeer 138). Then, the Company created Mord, a bear built around a human who retained much of his humanity for a while. They had become reckless with their experimentation, and Rachel states, “No one, not even Wick, knew why the Company hadn’t seen the day coming when Mord would transform from their watchdog to their doom–why they hadn’t tried to destroy Mord while they still held that power” (VanderMeer 4). This statement reveals the Company’s disregard for the consequences of their work and perhaps overconfidence in their ability to control nature. The price for disrupting the balance of nature was the destruction of civilization. The city returns to nature in a way. The humans must fight for survival, like any other animal or piece of biotech. Even at the end, with Mord dead and Borne neutralized, Rachel recognizes that the biotech “will outstrip all of us, and the story of the city will soon be their story, not ours” (VanderMeer 317). Nature fought back and won, and the city’s environment will inevitably return to its former glory. 

Another theme is the fear of animal sentience and what it could mean. Borne explores the definition of humanity and what it means to be a ‘person’. When Rachel realizes that Borne is verbal, she starts to treat him like a person. She tells him about her past, teaches him words, and tries to instill some sort of moral compass in him. Rachel tries to figure out what Borne is, and asks him, “Are you a machine?”, which she defines as “a thing made by people…made of either metal or of flesh. But not through natural biological means”. Borne is confused by this, and states, “Two people made you. You are made of flesh” (VanderMeer 45). This discussion serves to dissect what exactly makes a person, a person. It points out how similar humans, animals, and machines are at the base level. As creatures become more sentient, the line between them and ‘people’ begins to blur. Later, when Borne asks, “Am I a person?”, Rachel doesn’t hesitate to say “yes” (VanderMeer 65). This pivotal question confirms that something can be a person without being a human. This lack of distinction is a real problem in the realm of science, religion, and morality. In an interview with Gulf Coast magazine, VanderMeer states,

"Unfortunately, I feel that pushing back against anthropomorphism in terms of animal behavior science actually kept that field from recognizing animal sentience for a long time because they didn’t want to attribute intentionality to certain behaviors. And this then became propaganda, a foundational assumption a lot of us seem to have: the less sentient a creature is, the more okay it is to exploit or kill that animal” (Wyatt).

This distinction between animals and humans has helped bypass moral consequences. By deeming animals less sentient, people adopt the belief that animals do not feel pain, have emotions, or think the way humans do. They can be experimented on in ways humans can’t. The inconvenient truth is that many exploited animals are sentient enough that it shouldn’t be ‘okay’ to treat them as we do. If a human is harmed and fights back, it is considered justified. But if a creature with human-like sentience fights back, is it justified? The field of behavior science pushes back against animal sentience because the answer might be yes. This is reflected by Mord’s destruction of the city. The Company’s experimentation went unpunished until they created and exploited a creature with human sentience. Rachel admits that she “didn’t want Mord to be more like us…to be able to say when he murdered, when he pillaged, that he was a psychotic beast, a creature without the possibility of redemption, with no humanity in him” (VanderMeer 251). Rachel says this because admitting that Mord was a ‘person’ in the same way she and Borne were meant that his actions could be justified. Mord’s violence could stem from a mind that was sentient and intentional, and not so different from her own. So in the book as well as the real world, the fear of animal sentience comes from the loss of exploitability and the ugly similarities humans might share with animals.