mating attempts before the first successful one. There may be several more matings before the stag will seek out another mate in his harem. Females in their second autumn can produce one or very rarely two offspring per year. The gestation period is 240 to 262 days, and the offspring weigh about . After two weeks, calves are able to join the herd and are fully weaned after two months. The offspring will remain with their mothers for almost one full year, leaving around the time the next season's offspring are produced. The gestation period is the same for all subspecies. All red deer calves are born spotted, as is common with many deer species, and lose their spots by the end of summer. However, as in many species of Old World deer, some adults do retain a few spots on the backs of their summer coats. Red deer live over 20 years in captivity and in the wild they live 10 to 13 years, though some subspecies with less predation pressure average 15 years. Protection from predators Male red deer retain their antlers for more than half the year, and are less gregarious and less likely to group with other males when they have antlers. The antlers provide self-defence, as does a strong front-leg kicking action performed by both sexes when attacked. Once the antlers are shed, stags tend to form bachelor groups which allow them to cooperatively work together. Herds tend to have one or more members watching for potential danger, while the remaining members eat and rest. After the rut, females form large herds of up to 50 individuals. The newborn calves are kept close to the hinds by a series of vocalizations between the two, and larger nurseries have an ongoing and constant chatter during the daytime hours. When approached by predators, the largest and most robust females may make a stand, using their front legs to kick at their attackers. Guttural grunts and posturing is used with all but the most determined of predators with great effectiveness. Aside from humans and domestic dogs, the grey wolf is probably the most dangerous predator European red deer encounter. Occasionally, the brown bear will prey on European red deer. Red deer in folklore and art Red deer are widely depicted in cave art found throughout European caves, with some of the artwork dating from as early as 40,000