Secondly, they aren't white.. While some double merle dogs are almost pure white, they can go the complete range all the way up to a dog that you would think is a just a normal merle (most fall somewhere in the middle).
In between five and six months, your baby usually starts to sit up with your help, holding his head in an upright position, keeping the back straight. He may even be able to sit for a second or so without taking any assistance from you, before toppling down after a while [1] .
What's next. Most of the muscles babies use for rolling over are also used for sitting up independently and crawling. As your baby's neck, back, legs, and arms continue to get stronger over the next few months, he'll soon be able to sit on his own and scoot around the house. Most babies have mastered sitting up by six or seven months; crawling comes a little later.