The five week mark is when puppies start to resemble Chihuahuas. Their ears stand – sorta – their snouts armor defined and their domes start to pop a bit. Five weeks is also when they start to be a bit more adventurous and active. The boys are loving playing what the other dogs in the house and explore the living room during their play sessions. Even letting out some barks here and there! And just as predicted, their weight gain as slowed down substantially now that they are mobile. They are going to be small like their parents for sure!