In all of the animals, the male is significantly larger than the female. Also, all of the animals work in packs to hunt for their food. Humans have evolved and created modern agriculture, but when they were more primitive species, they hunted in packs.
Reproduction wise, all females sexually mature before the males do. Also, when the offspring is born they need support from their mothers or else they are helpless.
The behavior in all of the mammals are very similar. They all live in a group or community, in which size can greatly vary. There is a hierarchy in each community, and the males are at the top. There is very strong mother-offspring relationships and young usually never leave their community. The young also learn from their elders, and also like to play games while the elders hunt for food. Everyone has a system of communication, which consists of noises, gestures, facial expressions, or echolocation for dolphins.
Each of these mammals is fairly different in physical characteristics, eating habits, habitat, reproduction, and behavior. We picked these mammals mainly because they all have displayed very high intelligence and are said to be the most intelligent on Earth today.