Although male ligers and tigons are sterile, female ligers and tigons can produce cubs. In both ligers and tigons, the females are fertile and the males are sterile. Notably, ligers typically grow larger than either parent species, unlike tigons. Ligers or tigons will always have health problems. Ligers and tigons look just like their parents, only bigger or smaller. There are several issues caused by breeding ligers and tigons, mostly due to health problems. In the late 19th and early 20th centuries, tigons were more common than ligers. Some ligers are not sterile and can breed and survive like normal lions and tigers. White tigers have been crossed with lions to produce "white" (actually pale golden) ligers. Ligers are about the same size as the prehistoric "Smilodon populator" and American lion. Several AZA zoos are reported to have ligers. The only hybrid big cats commonly and deliberately bred in recent times are ligers. This list excludes hybrids such as ligers and tiglons. Ligers have a tiger-like striped pattern that is very faint upon a lionesque tawny background. However, ligers have occurred, and do occur, by accident in captivity.