- "Cows are not highly intelligent animals. An intelligent animal, smelling the blood, catching this brief glimpse of the future, would have bolted, kicked, fought. But no, maybe that is not true, either. Maybe an intelligent animal would understand that it was doomed and attempt to face the inevitable calmly."
Cattle (colloquially known as cows) are large domesticated creatures native to Earth. While the term cow is used as a general description, only an adult female is a cow. Non-castrated males are referred to as a bull, while castrated males are called steer or ox. A bull morph was acquired by Tobias, Ax and Kelly, with Ax also possessing a cow morph.
Tobias and Ax acquired steer in The Experiment; however, because neutering does not affect DNA, the DNA they acquired ended up being bull DNA. Ax also acquired a cow, mistaking it for a steer. In The Ultimate, Kelly acquires a bull as her battle morph.
- "So what do we have? One: We need to acquire specific cows. Two: We need to get their tags off and onto us. Three: We need to get on the truck and travel two miles without having to demorph. Four: We need to get inside the meatpacking plant and avoid being turned into Salisbury steak. Five: We find out what's going on there that has Visser Three so happy and bust it up." [...]
"So if we go in, we go in as cows? Cows? In a slaughterhouse? Does anyone else see a problem with that? Show of hands: Who would like to be a cow in a meatpacking plant?"
- ―Jake and Marco
In order to infiltrate a meatpacking plant that the Yeerks had purchased, the Animorphs decided to use steer morphs to enter the facility. Rather than having them all morph, Jake decided that Ax and Tobias would morph the steer since, if they had to demorph in a state of emergency, they would not expose the Animorphs as human. The others would then morph flies and stay inside the steer's nostrils. However, because steer are neutered bulls and DNA is unaffected by neutering, Ax and Tobias morphed bulls instead. Ax also briefly morphed a cow, mistaking it for a steer. When Kelly joins the Auxiliary Animorphs, she uses a bull as her battle morph.
- The Invasion (cow; mentioned)
- The Visitor (cow; mentioned)
- The Stranger (mentioned)
- The Andalite Chronicles (cow; mentioned)
- In the Time of Dinosaurs (cow; mentioned)
- The Departure (cow; mentioned)
- The Experiment (steer, acquired and morphed by Tobias and Ax, becoming bulls; cow, acquired and morphed by Ax)
- Elfangor's Secret (mentioned)
- The Reunion (mentioned)
- The Conspiracy (bull; mentioned)
- The Separation (mentioned)
- The Illusion (bull; mentioned)
- VISSER (mentioned)
- The Hidden (cow; mentioned)
- Back to Before (cows; mentioned)
- The Familiar (cattle; mentioned)
- The Resistance (bull; mentioned)
- The Ultimate (bull, acquired and morphed by Kelly)
- The Sacrifice (bull, morphed by Kelly)
- The Answer (cow; mentioned)
- The Beginning (cow; mentioned)