Reindeer
Reindeer are herd animals and live in groups. They live in groups of 10-100 reindeer, which are herds of only females or herds of only males. Reindeer go on long journeys between the warm and cold seasons. For this journeys the smaller groups form big herds of up to several 100,000 animals. Reindeer mate in October, and the males mate with as many females as possible.