Applegate followed up
The One and Only Ivan with a sequel,
The One and Only Bob, in 2020. In it, Ivan’s dog friend Bob goes in search of his long-lost sister with Ivan and Ruby’s help. On her website, Applegate lists E.B. White’s novel
Charlotte’s Web as the book that sparked her love of reading and writing, and its focus on kindness and helping others also appears in
Ivan.
Ivan is one of many novels, particularly for young readers, that draws attention to animal abuse and features an animal narrator. The most famous (and one of the earliest) examples is perhaps Anna Sewell’s 1877 novel
Black Beauty, in which a horse narrates his life story and his experiences with various owners—some kind, some cruel. Eliot Schrefer’s four young adult novels about humans and primates (
Endangered,
Threatened,
Rescued, and
Orphaned) looks at issues facing apes—such as poaching and the destruction of their habitats—from a human perspective. In addition, the memoirs of both Dian Fossey (
Gorillas in the Mist) and Jane Goodall (
In the Shadow of Man and
My Life With the Chimpanzees) were major forces in ape and primate research that led to the push to move the real-life Ivan out of the mall and into a zoo. Gerald Durrell also contributed to this research and pushed more broadly for captive animals to be housed in more naturalistic settings. He wrote a trio of books—
My Family and Other Animals;
Birds, Beasts, and Relatives; and
The Garden of the Gods—to raise money for his own zoo in Jersey.