Adult lions have no natural predators, excepting persecution by humans. Lions often kill and/or compete with other predators (leopards Panthera pardus and cheetahs Acinonyx jubatus). Spotted hyenas Crocuta crocuta defend kills or scavenged food from immature and female lions, but typically leave the food to a big male lion. Hyenas are known to kill lion cubs, juveniles, or weak and sick adult lions.
Lion cubs, if left alone, can be vulnerable to other large predators. However, infanticide is the primary threat to cubs.
Human poaching is a problem for lions. These animals are poached with wire snares, rifles, and arrows. Since lions are scavengers, they are particularly vulnerable to intentionally poisoned carcasses. There are still poachers that operate within some national parks in Africa. It has been estimated that in the 1960's, poachers were responsible for approximately 20,000 lion deaths per year in Serengeti National Park. Trophy hunting is allowed in 6 African countries.