The 21 Basic Mammal Groups
Primates (Order Primates)
Comprising prosimians, monkeys, apes, and human beings — about 400 species in all — primates in many ways can be considered the most "advanced" mammals on the planet, especially as pertains to their larger-than-average brains. Non-human primates often form complex social units and are capable of rudimentary tool use. Some species are equipped with dexterous hands and prehensile tails. There's no single trait that defines all primates as a group, but these mammals do share some general features, such as eye sockets encircled by bone and binocular vision (an excellent adaptation for spotting prey, and predators, from a long way off).
The 21 Basic Mammal Group caches were placed for HNY21.