The dromedary is diurnal (active mainly during daylight); free-ranging herds feed and roam throughout the day, though they rest during the hottest hours around noon. The night is mainly spent resting. Dromedaries form cohesive groups of about 20 individuals, which consist of several females led by a dominant male. Females may also lead in turns. Some males either form bachelor groups or roam alone. Herds may congregate to form associations of hundreds of camels during migrations at the time of natural disasters. The males of the herd prevent female members from interacting with bachelor males by standing or walking between them and sometimes driving the bachelor males away. In Australia, short-term home ranges of feral dromedaries cover ; annual home ranges can spread over several thousand square kilometres.