Animal repellent

Scarecrow in a field
Rat guards: steel or aluminum discs attached to the mooring line to prevent rats from boarding a ship
Ultrasonic bird repeller

An animal repellent consists of any object or method made with the intention of keeping animals away from personal items as well as food, plants or yourself. Plants and other living organisms naturally possess a special ability to emit chemicals known as semiochemicals as a way to defend themselves from predators. Humans purposely make use of some of those and create a way to repel animals through various forms of protection.