Applegate’s rendering of animal characters shows how experiences, such as parenthood, are universal regardless of culture or species. Much of the book deals with how Ivan’s understandings of himself and the world change as a result of becoming a father. Prior to learning about the twins, Ivan lives life as he always has, tending to his own desires while carrying the responsibility of being a leader. Upon learning that Kinyani is pregnant, Ivan’s world begins to change, though he is not aware of it at first. The subtle shifts in Ivan’s mindset reveal how little he knows and how ill prepared he is for parenthood, a predicament shared across species. When the twins are born, Ivan is no more prepared for his new job, but his instincts make him realize that his priorities must change. Through conversations with Bob and Ruby, Ivan learns that adaptation is common across species and that the struggles of parenthood are something that all creatures can understand. Ivan’s experiences are universal ones, which may make his journey relatable for readers, even though they are not gorillas.

The One and Only Family also addresses the universal experiences of trauma and memory.