They drink twice a day and also seek out needed mineral salt deposits. Wild horses can be separated into groups according to their age and gender. From birth to one year, both male and females are foals. In their second year, males are called a colt and a female becomes a filly. Colts and fillies are also called yearlings.
Colts mature in four to seven years to become a young stud or bachelor.
A female remains a filly until she is four years old or has been bred. Fillies who are bred or reach the age of four become mares. Mares with foals are usually three, more often four or more years old. When a bachelor heads his own band, he is then called a stallion. Wild horses lead a semi-nomadic lifestyle in the vast semiarid reaches of the West.