This chapter takes an evolutionary perspective to discuss the possibility that singing is an adaptive behavior developed by early humans to allow social bonding on a large scale, and it might do this via the release of endorphins. Methods for measuring social bonding and endorphin release are outlined, and two studies are described which demonstrate that singing is better than other activities at encouraging fast social bonding, and that it can work for very large groups. If singing is an optimally bonding human activity then it should be harnessed by modern societies in order to promote health and wellbeing.