She is about 12 or 13 years old and she is a mini Dachshund. When she is deeply asleep, she seems to snore sometimes, but other times instead of snoring, it turns into a hum. And sometimes her humming gets quite musical. She will do three rising notes in a row, or one note followed by a higher or lower note. If I hum back to her, we can get into a little echo chorus. It makes us laugh.

Has anyone ever known of a dog who hums little non-tunes in her sleep?