Part science lesson, part animal rights crusade, part morality tale, part coming of age story, Half Brother is a departure from bestselling author Kenneth Oppel’s better-known fictional worlds of flying ships and bats. All the same, it contains everything young readers could want: a teenage protagonist, an intriguing story, multiple plot twists, and even a cuddly baby chimp.

Ben Tomlin is the 13-year-old son of a behavioural scientist conducting a groundbreaking experiment to see if chimpanzees can learn human languages. Enter Zan, a newborn chimp the Tomlins raise as a human and teach to communicate using American sign language. The experiment proves exceedingly successful, and Ben grows to love Zan and even consider him a brother.

The trouble begins when the experiment loses funding. While Ben and his mother want to keep Zan, Ben’s father views him merely as a test subject. The family must decide whether or not to give Zan up to an uncertain and possibly perilous future.

Half Brother poses some thorny ethical questions. What makes a living being a “person”? Is it right to use animals in human experiments? What is language, and can a common understanding make humans and animals equals?

These questions are the novel’s best attributes, though they are diminished somewhat because their mouthpiece, Ben, is a two-dimensional character who stands as the book’s conscience. They are also occasionally obscured by a subplot involving Ben’s crush on a classmate, which veers into cliché and resolves with a whimper. Thankfully, Zan is the novel’s heart, and is effectively contrasted with Ben’s clinical, emotionally aloof father. This baby chimp will elicit laughs and even a few tears.

Even as it entertains, Half Brother leaves readers with plenty to consider about the way humans behave toward the many species that share our planet.