Trouble is a microscopic Chinese Crested Dog, mostly hairless, fine baby-girl blonde hair, fair skin with freckles. He was the runt of the litter, most were 8 lbs, he is 5.5lbs. He was not housebroken when I got him (it took over six months...) as he spent the first 18 months of his life in a kennel run, in excellent health but little if any socialization, dog or human. He loves riding in the car (Los Angeles to Santa Fe and back), sitting with me in cafes, and licking the bathtub. Mysteriously, he walks on a leash perfectly, stopping at curbs and staying on my left.  It's no surprise that he's very insecure. He sleeps in my armpit, under my chin or dangerously, down by my legs -- I've learned to be very careful about rolling over in bed. A non-naturally-occurring dog, obviously, of ancient lineage as a companion dog. Trouble is quite shy, unusual for the breed. He is of normal intelligence, but learns slowly due to his neglected upbringing. There is a "Powderpuff" variation that is covered in silky hair, and carries the genes for teeth and other useful things. Most 'Cresteds are about 12 to 15 lbs.
 
Molly is a Peruvian Hairless Dog. She has black skin, pink/mottled underneath, very coarse grey/agouti black hair heavy on her rump, tiny sprigs and tufts of hair on her upper surfaces, and a mohawk typical of the breed. I was on the rescue list for another 'Crested, got a call "well, we don't know what she is but she has no hair...". She was on Death Row in a small town pound.and was in horrible health (27 lbs., abcesses, ear infections, anemia, bleeding acne, etc), now 44 lbs. happy and healthy. She looks awful in the picture above-right; I'd had her only a few months then, she was still in poor health. She is extremely intelligent, communicates exceedingly well, very demanding, makes up games, throws a ball (OK, poorly), watches TV (really), talks like a Siamese cat, goes to the dog park every day. Her face scares little kids, though she is extremely gentle with everyone and everything, even plays carefully with bugs on the porch. Peruvian Hairless Dogs are exceedingly rare in the US; in Peru, so I am told, they were raised by the aristocrats (tiny minority rich folk, oppressively running poor country), who all got them selves killed in a leftist revolution in the 60's, serves 'em right I'm sure; peasants (sic) also slaughtered the Paso horses, and the dogs (hairless dogs, in Peru?). My working assumption is that she is actually a smugglee, rather than U.S.-bred, probably snuck into a container on a ship for someone to make a quick buck selling an exotic animal, and she escaped. They are a 'primitive' breed, ie. untouched by Western dog breeders. Evidence of them goes back 3000 years. Genetically related to the Mexican hairless dogs, Xoloitzquintli, aka Xolo, 'cept twice the size. They share many characteristics with, but are different from, Peruvian (or Inca) Orchid Dogs, which have much rounder heads, for starters. Molly has only two pairs of matching molars, a genetic trait (some have none).
 
In all mammals, the same genes express brain, teeth, skin.

We got hairless dogs 'cause we're allergic. Works. Poodles (et al) would probably work too.