Question:
I feel absolutely horrible bringing this up now when Pouncer just passed away, but I need to think about Cooper. He was an only cat until we got Pouncer last year. When she came to live with us, he was like a new cat. He was so happy, much more energetic, and he just loved having the company. Well, now that she's gone, I don't want him to be lonely. So, my questions... Do cats grieve? Do they need a mourning period? When should we bring another cat into the house? Does it need to be soon so he doesn't get depressed? Another cat is not going to replace Pouncer, in his heart or ours, but I want to do what's best for the kitty I still have, KWIM?
Answer:
Yes cats grieve, yes they do mourn the loss of a close companion, and it will take months before they get over it. Some will disagree with me; my opinion on getting another cat after a loss is to wait until they're pretty much over it. Some will say it's better to get another right away. I've only had experience with one, and that wasn't strictly a loss, though it was a loss to Rocket and to me; that was when Tommy had to be rehomed. And Rocket missed his buddy for many months. I adopted Twinkie about a month after Tommy left and it was too soon. Rocket didn't want anything to do with him. He kept moping around the house looking for Tommy for the longest time. Now he and Twinkie are buds, but I'm left wondering if it would have been better to wait.

Answer:
Cats definitely do have a period of readjustment after one of them is lost. Mike started a thread earlier this week on the subject...
I initially was going to get another cat immediately after I lost Callie, but ended up waiting about 3 1/2 months, for reasons other than letting Maggie & Kobi grieve. But in hindsight it was a good thing...there were several changes in dynamics and behavior during that time, that were actually for the better.
I think you need to assess how Cooper is behaving to determine when the time is right, but I would plan on at least 2-3 months maybe more...
Always remembering Onyx & Callie May
Answer:
In my case, Blueberry seemed to be lost without Precious, and I was an absolute mess. I was on the phone that very day, calling shelters and sobbing to the people who answered their phones. I wanted a female sealpoint Siamese immediately! Of course, what I wanted was Precious. I couldn't accept losing her; it was so sudden.
I wanted an adult cat immediately, as much for Blueberry as for me. However, I was told there was a black cat hanging around my property, and I thought perhaps God sent him (or her) to me. However, I never saw the cat, and began looking in Pet Finder. Finally, Stephie suggested The Siamese Rescue Organization, and after some false starts, I adopted Nina, a Balinese. (long haired Siamese) Perhaps that was better, because she looks more like Cinderella, Marie's cat, than a Siamese. She has her own personality, and I love her dearly. Blueberry and she got along from the beginning (after a slow introduction); it was love at first sight.
If I were going to get a kitten, I think I would have got one immediately. Circumstances prevented that, but it would have helped me immensely. Now, I wouldn't give up Nina. She's my baby.
So, I haven't really helped you much, have I? I think that taking a walk through a shelter would be a big help, because there are so many cats and kittens in need. And then, go with what your heart tells you. God bless.
Jeanie
http://www.theanimalrescuesite.com/
A dog, I have always said, is prose; a cat is a poem. ~Jean Burden