Living in the green grasslands of Australia, the grey kangaroo is the most social of the large marsupials. With last season's joeys fast approaching independence, the mothers become ready to mate again and the males have to make sure they are first on the scene to be in with a chance. A male sticks close by a promising female for several days to make sure he's the only one to mate with her. The most dominant male is likely to be the one to father most of the next generation and that's something worth fighting for. They box for the championship, with other males joining in a nearby fight. Young joeys also play fight to learn these important life skills.