Simplify the following text for a Grade 11 native English-speaking person.
Original: Trains of up to ten males -- often with the youngest and smallest male at the end of the queue -- may follow a single female in a courtship ritual that may last for up to four weeks ; the duration of the courtship period varies with location .
Simplified: Trains of up to ten males may follow a single female in a courtship ritual that may last for up to four weeks ; the duration of the courtship period varies with location .