The beginning of thumbsucking.
D000818:Animals; D001522:Behavior, Animal; D003020:Clothing; D004285:Dogs; D005260:Female; D005386:Fingersucking; D005500:Follow-Up Studies; D006184:Habits; D000882:Haplorhini; D006801:Humans; D006815:Hunger; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008310:Malocclusion / Q000517:prevention & control; D011574:Psychoanalytic Theory; D012018:Reflex; D012890:Sleep; D013391:Sucking Behavior