Even if your other pets do not seem to be emotionally close to the one that has died, they are aware that the household dynamic has changed and they might exhibit behaviors that are out of character. If they were close, they definitely can show signs of grieving, such as loss of appetite, depression, anxiety or searching for their missing friend. Treat them gently, with extra loving and wait for time to help them heal. There is anecdotal evidence to suggest that, if possible, having the pet smell the body of their deceased friend allows them to understand that their friend is gone.