Winter is spent in the underground part of the hill. Here, it is often free from frost.
An average sized anthill contains around 200,000 ants and a large perhaps a million. The hill can exist for decades, even up to a hundred years. About 2 million ants are born in the summer, or 2,000 every hour.
The anthill's slope absorbs sun heat well. This speeds up the hatching of eggs and larvae – the hill is actually an effective hatchery.
The ants open and close openings on the hill surface to regulate ventilation and temperature in the hill or to keep out rain water.