- Cats are in the same order as either monkeys or armadillos (Primates or Edentata; cats are actually Carnivora)
- Rats are in the same order as cats or monkeys (Carnivora or Primates; rats are actually Rodentia)
- Rabbits are in the same order as either armadillos or rats (Edentata or Rodentia; rabbits are actually Lagomorpha)
On a happy note, most of my students figured out the taxonomy with ease. I had to grade >100 papers to come up with these various errors (and many of the problems listed above are understandable based on our key).