After Lowell begins high school, he stops mentioning Fern. He begins dating a Mormon girl named Katherine “Kitch” Chalmers, who is one of nine children. At this point, Rosemary has almost completely stopped talking, having realized that she has an easier time at school when no one notices her. Her teachers complain about her lack of engagement, and her parents scold her. In Lowell’s senior year he is made point guard of the basketball team, which in turn boosts Rosemary’s social status. Yet just as a big game is coming up, Lowell comes home when he is supposed to be at practice. When Rosemary goes to find out why, he tells her: “Get the fuck out of my room” and “Don’t you ever fucking come in here again.”
Note that there is a pattern in Lowell’s life of choosing to spend time with religious people—first the Christian couple in the neighborhood and then the Mormon Kitch. Rosemary does not describe Lowell as having any religious beliefs himself, and thus this choice of company can be interpreted as an act of rebellion against his father. Unfortunately, it is Rosemary herself who receives the brunt of Lowell’s rebellion. Ostracized at school, she cannot even retreat into the comfort of her family and is thus totally alone.
At dinner Lowell behaves normally, but later that night he withdraws all his money, packs a bag, steals his father’s laboratory key, and liberates all the lab rats from their cages. He then gets a bus to Chicago and never returns. After this, Rosemary’s father is only able to work with graduate students whom all the other professors have rejected. Rosemary’s mother never emotionally recovers from Lowell’s absence. At first, Rosemary thinks that Lowell will surely come back in time for her birthday. Her parents hire a private investigator to find Lowell, and when this leads to nothing they hire a second investigator. Rosemary begins sleeping in Lowell’s bed and one day finds a note from him that says: “Fern is not on a fucking farm.” She doesn’t tell anyone about the note.
Lowell’s sudden departure from the family contains elements of a typical teenage rebellion against one’s parents, but is clearly also motivated by his ideological concerns and (as Ms. Delancy points out) his strong sense of justice. There is thus an extent to which Rosemary’s parents must blame themselves for Lowell’s absence. If they had not raised him alongside a chimpanzee and encouraged him to treat Fern like a sister, he may have not developed such powerful beliefs about animal rights. On the other hand, would this have really been better? Is it not desirable, the novel asks, for all people to have the same sense of justice as Lowell?
At 8 or 9, Rosemary used to dream about herself and Fern living on the farm together, a fantasy inspired by Peter Pan and the Swiss Family Robinson. She reasons that she would live a happy life as an orphan. With Lowell gone, Rosemary’s social status has dropped again. On the first day of seventh grade, someone tapes a picture of a chimp to the back of Rosemary’s backpack, and she doesn’t realize it until a teacher removes it. At home that night, Rosemary cries, wishing Lowell would come back. She doesn’t tell her mother, who is in too fragile a state to handle it, or her father, who she believes would be no help.
Rosemary’s belief that she would live happily without her parents likely emerges from a childish naïveté. Although she resents her parents’ secrecy and dishonesty, she does not truly know what life would be like without them. At the same time, her fantasy speaks to the unparalleled relationship she has with Fern, which is not even comparable to her connection with Lowell. As Rosemary pointed out earlier, she and Fern were raised as twins and thus Fern’s loss is uniquely devastating.
Luckily, there are kids in school who are considered even weirder than Rosemary, and she is no longer bullied after that first day. At night she hears her parents worrying about how silent she is these days. Occasionally they receive postcards from Lowell from different locations around the country. Eventually, they stop trying to find him. Then, one day, two men from the FBI arrive at the Cookes’ house and ask to speak to Lowell. They believe that Lowell is a suspect in a fire that caused millions of dollars’ worth of damage to a veterinary laboratory at UC Davis. Rosemary concludes the chapter by noting that not all of the rats Lowell set free from their father’s lab were captured, and that for years after there were sightings of lab rats all over Bloomington.
Even in his absence, Lowell continues to indirectly rebel against his father and the entire institution of scientific research on animals. Again, the absence of a family member thus becomes a kind of presence. While the family do not actually see Lowell, there are reminders of his existence everywhere; not only in the dramatic example of the FBI showing up but also in the postcards he sends and the lab rats that continue to be spotted around the city. While Lowell may have left his family behind, the connection between them cannot easily be broken.