Herds are usually made up of between 6 and 12 elephants. However, groups of between 12 and 20 elephants are also not uncommon. If the herd becomes too large, some of the daughters will break away with their young to form new groups on instruction from the matriarch. This may happen if the food - and water supplies are not sufficient to sustain the entire herd as they move through a specific area.
As they travel, the daughters and their calves follow the lead of the matriarch elephant, walking behind her in single file. Calves follow their mothers obediently, holding on to their tails with their strong little trunks.
As the first and oldest mother, the matriarch is instrumental in teaching her daughters how to care for their own young. Once they start to bear babies, their sisters will assist in childcare. This provides training for them, preparing them for their own first calves. Elephant mothers are attentive to the needs of their young. Babies are born with almost no instinctive patterns, nearly everything they do has been taught to them by their mothers and aunts. What they get taught will vary according to the matriarch and her herd different groups face different dangers and bear different responsibilities. The matriarch will determine what it important for that specific herd and mothers teach the young ones accordingly.
When she dies, she is normally succeeded by her closest relative from the herd (usually the oldest daughter).
Here is more on the role of the Matriarch: Click Here