A usually calm cat was the alarm that saved the lives of its two owners.

Every year, roughly 430 Americans die of carbon monoxide poisoning, and Kevin and Annette Shanahan of Reedsburg, WI would have also been statistics if their cat hadn't saved their lives. The usually calm Gracie began banging against the couple's bedroom door. This awoke Kevin who found Annette struggling to breathe in a chair in the bedroom. The couple called 911 and were hospitalized for exposure to lethal amounts of carbon monoxide.

The Shanahans hadn't checked the batteries in their CO2 alarms in sometime and would have likely died if not for Gracie. Their story is a great reminder to check your own alarms and your gas - powered appliances for leaks.