Given names often turned into family names when people were identified by their father's name. For example, the first name Ahrend developed into the family name Ahrends by adding a genitive s-ending, as in Ahrend's son. Examples: Ahrends, Burkhard, Wulff, Friedrich, Benz.
OK the definition you have used for crouching associates it with stooping (which on Wikipedia redirects to bowing. Squatting essentially involves bending at the knees and hips. If there is any bending at the waist (and maybe lowering of the head) then that is considered stooping.
Cruising, crawling and sitting back down. Your baby might be cruising soon, standing up and moving while holding onto furniture. Learning to sit down afterwards is a whole other ball game â most babies find this much more difficult that the act of standing up.