I hate living in the desert! Damn cactus rats keep eating my cats!
A cactus rat is a slang term for a porcupine. The sharp quills on the porcupines back and tail represent the prickliness of a cactus. A rat is also a long distance family member of a porcupine (both are rodents).
Bob, don’t let the dog outside tonight. Those darn cactus rats a roaming the yard again!