The domestic pig of today originates from the European wild boar, although there are still wild boars today. The domestication of pigs is thought to have started about 7000 to 8000 BC. The modern domesticated pig has a smaller head in proportion to the body, a mostly curled tail, less hair and a thicker layer of fat than wild boars. They now breed at any time of the year with more than one litter annually. While the physical appearance has changed, the domesticated pig still has most of the behavioural repertoire of the wild boar. Until the 1950’s, farming was often mixed (crops and livestock) with only a few pigs. Female breeding pigs were kept outside in the summer, with a wallowing pit and shade. Animals kept indoors were housed in loose pens, normally bedded with straw.