I occasionally lurk the forums and have a private little chuckle at the stories that are shared. Also when i feel the need to bring myself back to reality i will go through the Rainbow Bridge section to prep myself for the inevitable.

It saddens me to say that we recently lost our girl at the age of 17. My wife got her when she was younger and she had been her constant friend and companion through moves. She was special to me because she made me a dog person, also being a Basenji Lab Cross, she was out introduction to the wonderful world of Basenjis. Many people might not have seen it, but her mannerisms and quirks prepared us for our little girl, Bassit.

When Bassit entered our lives at 6 months old, Cleo was already into her 14th year and had very little patience for a other dogs, let alone a basenji pup. They never seemed to really click, but ocasionally they would sleep curled up in a ball together. But more often then not The little one would kick the older one out of her bed or teasingly bite her tail.

My question is does she know she isn't coming back? Does she care?

I think animals know. Whether they miss the departed one is another question. Some definitely grieve. Others may be just as happy to not share your attention anymore. I have seen it both ways with mine.

I agree with eeeefarm. They definitely know when one is gone. Our previous 2 dogs, not B's, were a year apart. Misty went first after suffering from diabetes for months. Blacky looked around for her for a bit, but wasn't really bothered by the fact that she was no longer there. They were never very close and in the 10ish yrs they spent together only slept within a foot of each other a handful of times. They were fine with the other, just never had much interaction. I will say I had a rabbit, Henrietta, that passed years ago and she and my cat (still going strong at 19 or so) were very close. He definitely grieved over and missed her, though we had a new baby bunny days later and he promptly took up the role of care-giver and self-appointed protector for her.

I'm so sorry for your loss. Your Cleo reminds me so much of our Lab/B cross, Kia. At 13, she's starting to get stiff and impatient with her two Basenji brothers, but she's also been a kind and patient "nanny dog" to a number of lost-soul male Basenji fosters.

To suggest an answer to your question, same sex dogs don't always bond as well as opposite genders. Kia and my first B, Sam I Am, never got along–both females, so not surprising. And most of my male foster/forever Basenjis have worshiped the two females--but only tolerated each other.
But don't be surprised if Bassit starts displaying Cleo's mannerisms or behaviours if you ever adopt a little brother for her. When my Sam I Am passed away, very uncharacteristically Ben took up her duties as "Little Mother" to the next foster, surrendering his food bowl, cleaning and hovering like a mother hen-- with the same devotion that Sam had lavished on him.