The mothers have short pregancies so the puppies aren't fully developed when they leave the womb.
Puppies are born completely toothless and within 4 weeks they will start to grow their baby teeth. When they reach six months they should have all 42 of their adult teeth.
Puppies need up to 15-20 hours of sleep per day. Naps that pupies take are very important to develop their brain, muscles, and immune system.
The first confirmed identical twins was in 2016, Kurt de Cramer performed a C-section on an Irish Wolfhound. Instead of finding every puppy with its own placenta, he noticed that two puppies shared the same placenta. Later they tested the puupiees and found that they were identical genetically.
Puppies with a light-coloured coat can be born green, though it is rare. This is due to a green pigment in dogs placentas called biliverdin. The puppies fur gets stained and comes out green. It isn't permanent and disappears withinf a few weeks.