When left, girls cry and boys go jiggle the latch. When older, girls call for help and boys forget their language skills and jiggle the latch. Preschool boys cry more and play in larger groups than girls. Boys are more likely to stand their ground when hit. When given attention by adults, the time they spend playing doubles.
Boys laugh and tease more.
See also developmental stages in the instructors' notes. One boy is different than two boys. Boys in all-female worlds, asked to do things they're not developmentally ready to do, get frustrated. Boys try to establish power and increase status in group, girls tend to avoid conflict. For girls, essence of a friendship is talk, for boys the essence of friendship is doing, and boasting and threatening and competition.