Fraser isn't sure of the other parent, but considering the vastly limited choices, one can easily theorize the other parent was a sled dog. This would explain why Dief looks so much like a Husky, from the eye coloration to the curling of his tail. Dief is, in fact, a wolf-hybrid, popularized by pet dealers these days. Wolf puppies are born with blue eyes, which then become a golden color as they reach maturity. Although a wolf's vision is excellent, for the first few weeks of birth they are unable to focus their eyes properly.
Wolves can smell their prey up to a mile away.
Wolves have litters according to their environment. Wolves mate in the winter or early spring, and the pups are born approximately two months later. Wolves live in packs, anywhere from 8 to 20 at a time. Packs are dominated by the 'alpha' male or 'female', who determines who eats first, etc. There is a definite hierarchy of dominant and submissive within the pack, and wolves can even sense this tendency in humans.