What's A Warthog "Sounder"?

Warthogs live in groups called sounders.

 Picture from Digital Journal

Younger male warthogs live in bachelor groups, but leave on their own when they become adult.  They will only join a new sounder with a sexually receptive female warthog.  While females tend to stay in their natal groups, the males will leave to wander, but remain within their home range, or area.  The females live in their sounders with their young and other female warthogs.