A video of a cat named Willow went viral on TikTok, showing her waiting for breakfast the morning after losing her sister Lucky. The heartbroken reaction touched the hearts of millions of viewers, with many expressing sympathy for Willow and her owner. Comments poured in, with people sharing their own experiences of pet loss. The American Society for the Prevention of Cruelty to Animals (ASPCA) conducted a study on companion animal mourning, revealing common behavioral changes in pets after losing a companion. If you have cute pet videos or pictures, send them to [email protected] for a chance to be featured in our Pet of the Week lineup.