zOMG TINY ANIMALLLLZZZ! OK, just had to get that out of our systems. Now here's some science.
There are three kinds of dwarfism in dogs: Ateliotic dwarfism results in a miniature version of a larger dog; micromelic achondroplasia results in a dog with a normal-sized body and short legs; and brachycephalic achondroplasia results in a dog with shortened bones in either the snout and upper jaw or the lower jaw.
Asian dog breeds like the pug, the Shih Tzu and the Pekingese display all three kinds of dwarfism, so they are miniature and have short legs and squished-looking faces -- making them completely irresistible to their owners.
Click through the gallery to see other dwarf pets whose owners wouldn't have them any other way. KIMIHIRO HOSHINO/AFP/GettyImages
Dachshunds are mainly micromelic dwarf dogs, which means their longest bones -- legs -- are affected by the condition. Dachshunds can also have ateliotic pituitary dwarfism, meaning they can be short-legged and "miniature," like Yorkies and Italian greyhounds. Don't let their gregarious and excitable nature fool you: Dachshunds are fearless, natural-born hunters. Their ancestral prey is the ferocious badger. CRAIG LASSIG/AFP/Getty Images
Pembroke Welsh corgis and their cousins, Cardigan corgis, are dwarf dogs thanks to genetic breeding. They have the same kind of genetic mutation -- achondroplasia -- that humans can experience. It gives corgis a terrific advantage that has helped this dog survive since the 10th century.
Corgis were bred to herd cattle in Wales. Because they're small, they can easily dodge a feisty bovine kick. Their muscular bodies make them fast runners and their thick coats let them work a long day in the cold, damp countryside. They are jovial and intelligent companions, but don't be surprised if you start playing fetch with a corgi and end up neatly corralled, instead. TIMOTHY A. CLARY/AFP/Getty Images
The Munchkin cat is also genetically bred to have a normal-sized body and short legs. Like corgis and dachshunds, these cats are speedy and agile. They're also extremely playful and social cats. They're known to sit on their hind legs like rabbits when their curiosity is piqued. Dwarf cats have been identified in all parts of the world since 1944. In 1983, a Louisiana music teacher rescued a short-legged, pregnant cat that became the foundation for the breed now called the Munchkin, according to The International Cat Association. She named the litter for their resemblance to the "Wizard of Oz" characters. EPA/BARNABAS HONECZY /LANDOV
Pigs are highly intelligent creatures, but livestock hogs are impractical as pets because of their size. Miniature pot-bellied pigs, however, are bred for dwarfism and grow to weigh between 120 and 150 pounds. They are docile animals that can be house-trained. They can also develop a repertoire of delightful tricks, which makes them a suitable alternative to dogs for many pet lovers. JEFF HAYNES/AFP/Getty Images
Which tiny rodent pet is even cuter than a hamster? The African pygmy mouse, of course! This mouse lives in the wild in sub-Saharan Africa but it's also bred as a pet all over the world. African pygmy mice are one of the smallest rodents -- they can range from 1 to 3 inches long -- and can easily sit on a penny. They are very social animals, so it's good to have more than one, but this is not a pet for snuggling: They're so small that they can be injured by handling. Hulton Archive/Getty Images
Miniature donkeys hail from Sicily and Sardinia, where they have been used as beasts of burden since the 18th century. They were introduced abroad in the 1920s, where they became beloved pets, especially in the United States and United Kingdom. They are naturally small because of isolation and food sources, an example of what scientists call "island dwarfism." Owners cite their tender, loving disposition and intelligence as reasons these spunky animals won their hearts. Fox Photos/Getty Images
The African pygmy goat (pictured here), the Nigerian dwarf goat and the Australian miniature goat are all descendants of naturally small African goats. As adoring as any dog or cat, goats make great pets and therapy animals because they do not bite. They are often dehorned so they can live in homes. Gareth Cattermole/Getty Images
Shetland ponies, one of several breeds of miniature horses native to the United Kingdom, were first bred as mining ponies. Nowadays, miniature horses are bred either as companion pets or to competitively show and jump. They're also often used as therapy animals. With a life expectancy that can reach 40 years, they're as intelligent as dogs -- some owners might argue, even smarter. Jeff J Mitchell/Getty Images