Columbian mammoth tusks were generally less twisted than those of woolly mammoths. The short, tall skulls of woolly and Columbian mammoths are the culmination of this process. Cave paintings of woolly mammoths exist in several styles and sizes. It did not live in Arctic Canada, which was inhabited by woolly mammoths. Wild sheep were more hairy than woolly. Two spear throwers shaped as woolly mammoths have also been found in France. One hypothesis is that humans hunted large mammals, such as the woolly mammoth, into extinction. The diet of the woolly mammoth was mainly grasses and sedges. The thriving population lived by hunting game such as horses, bison, mammoth and woolly rhinos. The resulting calf would have the genes of the woolly mammoth. The fur is short, woolly and dense. Distortion in the molars is the most common health problem found in woolly mammoth fossils. The group includes the fluffy white woolly aphids. Its tail was intermediate in length between that of modern elephants and the woolly mammoth. DNA studies have helped determine the phylogeography of the woolly mammoth.