For protection they carry swords and long spears. The Masai are basically nomads that tend large herds of cattle. Traditionally, they were truly nomadic, moving their herds and homes as they saw fit. Today, most Masai establish a home base from which their cattle are moved as necessary between the wet and dry seasons. The need to roam about is directly tied to the availability of food for their live stock.
Masai life revolves around the cattle and goats.
The livestock provides their income, meat and milk. The cattle are a sign of wealth. With large herds they need many children to take car of the livestock and have multiple wives to bear them. The children start taking care of the goats shortly after they learn to walk and eventually graduate to tending cattle when 5 or 6 years old. We saw many instances of very young children taking care of several dozen cows.