- "And then, at last, the horn. It grew from my face, down where my nose had once been. Long, curved, dangerous. A primitive, blunt weapon. A horn that could have impaled an armored knight. But despite the formidable body, the terrifying horn, the power of the rhino, its mind was peaceful, placid. Basically, it just wanted to eat and to be left alone. It was watchful but not scared or angry."
- "That face, that horn, hovered inches from me, as the rhinoceros sniffed me and I prayed he wouldn't impale me. He was growing more agitated. He was upset by what he was watching. No surprise. It would have upset me, too, watching a boy squirm and mutate his way out of a bird. And then I had a hand. I stuck it out, half-blind, and touched the horn. I wrapped my still-emerging fingers halfway round it, and I focused with all my mind. When you acquire animals, they go into a sort of trance. Except sometimes they don't. And if this was one of those times, the rhino would trample me and use me for target practice with his horn. I focused on the beast. I focused and felt him become a part of me."
Jake acquired a rhinoceros morph in The Warning, needing a morph to save Rachel and Ax from Joe Bob Fenestre's clutches. Despite the crowd, Jake landed on the rhino in his falcon morph and acquired the rhino. Marco acquires a rhino in The Solution, opting to mirror Jake's morph rather than acquire elephants like the others. A rhinoceros was also acquired by Tricia in The Ultimate to use as her battle morph.
After Rachel and Ax are trapped in Joe Bob Fenestre's mansion, with the morphing clock ticking, Jake realizes he must break into the house, despite the heavily armed security. He opts for a rhinoceros morph, as it would be capable of charging into the house and surviving bullet wounds. Jake also uses the morph in The Discovery to deal with some human-Controllers. A short time later, when the Animorphs decide to storm the Marriott Resort, guarded by both domestic and international security forces, Jake and Marco use the rhinoceros morph to survive the bullets while dishing out significant property damage, while the others use the elephant morph. In The Exposed, Jake morphs the rhinoceros to break into a flophouse and uses it once again in The Conspiracy to break into Chapman's house. The morph was later adopted by Tricia, who used it as her battle morph, and was eventually killed while in rhinoceros morph. A human-Controller also used a rhino morph to fight the six core Animorphs and James' team in The Sacrifice, and was killed in morph.
- The Invasion
- The Stranger
- The Warning (acquired and morphed by Jake)
- The Decision (mentioned)
- In the Time of Dinosaurs (mentioned)
- The Discovery (morphed by Jake)
- The Solution (acquired by Marco; morphed by Jake and Marco)
- The Extreme (mentioned)
- The Exposed (morphed by Jake)
- The Conspiracy (morphed by Jake)
- The Diversion (mentioned)
- The Ultimate (acquired and morphed by Tricia)
- The Sacrifice (morphed by a human-Controller)
- The Answer (morphed by Tricia)