Likewise, unless you’ve evaluated the temperament of a puppy’s parents, you can’t project what the puppy’s adult temperament might be with any level of certainty. You can’t assume that just because a puppy looks like it has a specific breed in his background that it means that he’ll act like that breed. Unfortunately, even some purebred dogs are not indicative of their breed, meaning they may not look or behave according to the written breed standard which specifies how the breed is supposed to look and act.
In short, if you want to have a better understanding of the likely characteristics of a mixed breed puppy, you need to see the parents. You can’t accurately guess at the breed background of a mixed breed puppy just by its appearance. Be wary of mixed breed dog descriptions that reference specific breeds you find at humane societies, rescue groups, and pet stores. Unless the parentage of the dog is known, any reference to their breed make-up is likely just speculation based solely on the dog’s physical appearance.
If you like the health benefits of a mixed breed dog but don’t want the uncertainty of adopting a puppy, you can look for an adult mixed breed dog. When you get an adult mixed breed, you can see the “finished product” for yourself. You know how large the dog is, you can judge how much exercise it may need, and evaluate its temperament. While you lose some of the benefits of adopting a puppy, you gain knowledge of the dog’s adult size and can evaluate its temperament.
Consider the Source. Finally, when researching mixed breed dogs, consider the source. Getting mixed breed dogs from certain sources inherently includes more risk than others. Adopting a mixed breed from an animal shelter, for example, carries more uncertainty than getting a mixed breed from a friend who tells you the dog is housebroken, likes to chase cats, is great with kids, and digs in the yard.
When you adopt from an animal shelter, you have no way of knowing the dog's background, whereas when you get a dog from a trusted friend, you may have a reasonably good idea of the dog's expected size and temperament. However, being able to see the parents is always an advantage, especially if you are getting a puppy, so you can make an better guess about the likely size of the adult and other physical traits (like shedding) that may be important to you.