During the first first few weeks a mother carries her puppies by the scruff of the neck. This method is no longer appropriate by the time we start training a puppy to become housebroken, and it's awkward to boot. Nor should you pick up a puppy under his arms like a baby. The pup's shoulders are attached to the rib cage only by the serratus magnus muscle. If you pick a puppy up under the arms, you will pull its shoulders away from the body. This hurts the puppy and you want the puppy to be comfortable when carried. The best way to go about it is to put one hand under the puppy's rib cage and the other under his rear end.