The fact that elephant herds are matriarch-led is most evident in the manner in which elephants mate. Bulls stick to a bachelor (all-male) pod in which they live and travel. When one of the bulls desires to mate, he will search out a herd of elephant cows. He will select a desirable cow and pursue her until she is ready to mount. She has the final say regarding whether or not she accepts the bull's advances. Once he has mated with her, he returns to his bachelor herd, having nothing to do with the rearing or caring of the young.
Likewise, when the male calves in the herd mature into adolescence, they will also break away from the herd, gradually at first, and form bachelor pods with their peers. Adolescent females stick to their main herd until adulthood and, sometimes, even until death, depending of the resources available and the size of the herd.
Like humans, elephants are capable of forming very special bonds with their friends and family members. These relationships start at the core of the herd, i.e. mother and calf. But, they radiate out, and there have been astounding reports of lifelong bonds between elephants that have transcended time and even distance apart.
Elephants value their family structure, perhaps more so than many other animals. They are naturally outgoing, sociable animals and, as such, enjoy the interaction with fellow family- and herd members. Although structured, the herd is fluid enough to compensate for unforeseen circumstances (such as the death of one of the mothers, where other mothers allow the orphaned calf to suckle). Such ties are rare, and the empathetic and insightful nature of these magnificent animals continues to lure researchers deeper and deeper into the elephant psyche.
Here is more about Elephant Families