Oh gosh, yes. After my tuxie Peeka died, her blackie brother Boo walked all through the house calling her, looking around corners, etc. And after my dog Charmin died, her daughter Daisy howled like a little wolf for 6 months and died shortly thereafter herself. My late friend Helen had 2 pet geese and when the female died, the male thrashed his head against the side of the house as he cried. It was heartbreaking. Absolutely cats mourn; I believe all animals do. I think that's partly why we bond w/them so.
