It’s a scientific fact: Killing or removing feral cats who live outdoors won’t reduce the size or eliminate the feline population across time. It may sound counterintuitive but it’s true, and the Vacuum Effect is the reason why. We’ll explain in the latest video in our All About educational series: All About the Vacuum Effect.

Alley Cat Allies has been advocating for a greater understanding of The Vacuum Effect and how it applies to community cats for many years. Now with our All About The Vacuum Effect video, we’re making it easier than ever for you to learn and share this information with your friends, family, co-workers, and community—including policymakers.

So, check out the video and discover The Vacuum Effect; why catching and killing or “euthanizing” community cats, sometimes called stray or feral cats, is a cruel, ineffective, and endless cycle; and why Trap-Neuter-Return (TNR) is the only humane and effective approach to stabilize community cat populations.

For another easy way to spread awareness about the Vacuum Effect, our JUST THE FACTS: The Vacuum Effect cards are available for purchase and free PDF download.

Watch this video on YouTube at

Visit our YouTube channel at for more videos with the information you need to know to save cats’ lives.