Q: We bought our 8-year-old dog, Callie, from a local family, and we're still in touch. I've often wondered if Callie would recognize a sibling. Is this possible? — J.K., Cyberspace
A: All these years later, the chance your dog would recognize a litter mate is a definitive "maybe."
Veterinary behaviorist Dr. Lore Haug, of Houston, explains: "Siblings most certainly can recognize one another. But when they're separated at a young age, there's no way to consciously remember. Still, it seems that at some olfactory level we don't fully understand, even litter mates separated at a young age probably do recognize one another on a subconscious level."
If Callie is not spayed, it's possible she'd resist hooking up with a brother. This ability is beneficial for the species.