Dogs often perceive vacuum cleaners as loud and intimidating threats due to their sensitive hearing and instinctual fear of unfamiliar, noisy objects. This can trigger a fight or flight response, leading to behaviors like barking, hiding, or chasing the vacuum. To help dogs feel more comfortable, gradually acclimatize them to the vacuum's presence and sound. Start by having the vacuum off and nearby, rewarding calm behavior with treats. Increase progressive exposure, eventually turning the vacuum on while offering positive reinforcement. This method can reduce anxiety and build a more positive association with the vacuum cleaner.