More dogs and cats give birth in spring than other seasons, so if you're looking to adopt a pet when it's young, you'll have the biggest selection now. The best things about small puppies (aside from their irresistible cuteness) are that they are easily portable and as adults they tend to live longer than big dogs. Small puppies come in different colors, sizes, and temperaments. The five breeds here show the most popular small dogs as puppies and tell what's special about each type. Note: Since the world already has more dogs and cats than homes, consider adopting a rescue dog.