PBS | 8:00 pm

The three-part miniseries "Primates" continues with the middle episode "Family Matters," which reveals how primates have the most complex social lives of any animal group on Earth. Leaf monkeys actually compete for the privilege of babysitting an infant, but rally together when the ape tot is threatened by a python. Gibbons teach the secrets of their treetop acrobatics to less experienced playmates, and intimate video footage shows a gray slender loris mother in Sri Lanka caring for her twins.