510 ILCS 5/2.16: Owner.

"Owner" means any person having a right of property in an animal, or who keeps or harbors an animal, or who has it in his care, or acts as its custodian, or who knowingly permits a dog to remain on any premises occupied by him or her. "Owner" does not include a feral cat caretaker participating in a trap, spay/neuter, vaccinate for rabies, and return program.