I grew up with black rat terrier and after having miniature schnauzers for 35 years, we adopted a stray rat terrier/chiuaua mixand enjoyed her presence for 8 years. We did not know her age when we got her but she was not spayed but we had it done. She was my husband's walking companion on his neighborhood watch patrols and my lap companion. We have no other pets but miss her terribly. The vet though she had a stroke or a slipped disc. One morning she could not use her hind legs at all.