Hashikawa K, Hashikawa Y, Falkner A, and Lin D (2016) The neural circuits of mating and fighting in male mice. Current Opinion in Neurobiology, 38:27-37. HIGHLIGHTS • Mating and aggression can be divided into appetitive and consummatory phases. • In rodents, conspecific volatiles activate the main olfactory system to initiate approach towards a social target. • Social investigation engages the accessory olfactory system and specifies subsequent consummatory actions. • Hypothalamus is essential for the expression of both mating and fighting behaviors. • Periaqueductal gray represents a key region to relay the hypothalamic signal to the spinal cord for motor execution of social behaviors.