Like modern beef, modern pork comes from much younger and leaner animals than was true a century ago. Pigs are typically slaughtered at six months and 220 lb/100 kg, just as they reach sexual maturity, when the connective tissue is still relatively soluble and the meat tender. Individual cuts of American and European pork generally contain half to a fifth of the fat they did in 1980. Pork is a pale meat because the pig uses its muscles more intermittently than do cattle and sheep, and therefore has a lower proportion of red muscle fibers (around 15%). Some small Chinese and European breeds have darker and significantly more flavorful flesh.