
Panthera leo melanochaita is a lion subspecies in Southern and East Africa. In this part of Africa, lion populations are regionally extinct in Lesotho, Djibouti and Eritrea, and are threatened by loss of habitat and prey base, killing by local people in retaliation for loss of livestock, and in several countries also by trophy hunting. Since the turn of the 21st century, lion populations in intensively managed protected areas in Botswana, Namibia, South Africa and Zimbabwe have increased, but declined in East African range countries. In 2005, a Lion Conservation Strategy was developed for East and Southern Africa.
Results of a phylogeographic study indicate that lion populations in southern and eastern Africa form a major clade distinct from lion populations in West Africa, Central Africa and Asia. In 2017, the Cat Classification Task Force of the IUCN Cat Specialist Group subsumed lion populations according to the major clades into two subspecies, namely P. l. leo and P. l. melanochaita. Within P. l. melanochaita three subclades are clearly distinguishable. One from northeastern Africa, another one from southwestern Africa and a third one from southeastern Africa.
The type specimen for P. l. melanochaita was a black-maned lion from the Cape of Good Hope, known as the Cape lion. Phylogeographic analysis of lion samples from Gabon and the Republic of the Congo indicate their close genetic relation to P. l. melanochaita samples from Namibia and Botswana. It has been referred to as the Southern lion, Southern African lion, East-Southern African lion and the "southern subspecies".

The Serengeti and Maasai Mara National Parks and Selous Game Reserve are lion strongholds in East Africa with stable lion populations
In East and Southern Africa, lion populations declined in:
In Ethiopia, where lion populations declined since at least the early 20th century due to trophy hunting by Europeans, killing of lions by local people out of fear, for illegal sale of skins and during civil wars.[40] As of 2009, between seven and 23 lions were estimated to live in Nechisar National Park located in the Ethiopian Highlands. This small protected area is encroached by local people and their livestock. In 2012, lions were documented in cloud forest habitat of Kafa Biosphere Reserve.
Somalia since the early 20th century. Intensive poaching since the 1980s and civil unrest posed a threat to lion persistence.
Uganda to near extinction in the 20th century. In 2010, the lion population in Uganda was estimated at 408 ± 46 individuals in three protected areas including Queen Elizabeth, Murchison Falls and Kidepo Valley National Parks. Other protected areas in the country probably host less than 10 lions. Lions in Queen Elizabeth National Park form a contiguous population with lions in Virunga National Park.

Kenya in the 1990s due to poisoning of lions and poaching of lion prey species. At least 108 lions were killed between 2001 and 2006 in the Amboseli−Tsavo West−Tsavo East National Park network. As of 2006, there were an estimated 675 lions in the Tsavo national parks, out of the 2,000 total in Kenya. Between 2004 and 2013, lion guardians around Amboseli National Park identified 65 lions in an area of 3,684 km2 (1,422 sq mi). Lion populations in Kenya and Tanzania are fragmented over 17 patches ranging in size from 86 to 127,515 km2 (33 to 49,234 sq mi).
Rwanda and Tanzania due to killing of lions during the Rwandan Civil War and ensuing refugee crisis in the 1990s. A small population was present in Rwanda's Akagera National Park, estimated at 35 individuals at most in 2004. Lions were reintroduced to this national park in 2015.
Malawi and Zambia due to illegal hunting of prey species in protected areas.
Botswana due to intensive hunting and conversion of natural habitats for settlements since the early 19th century. In Northern Tuli Game Reserve, 19 lions died between 2005 and 2011 due to poaching, trophy hunting and snaring.

Namibia due to massive killing of lions by farmers since at least the 1970s. In 2010, the small and isolated lion population in the Kalahari was estimated at 683 to 1,397 individuals in three protected areas, the Kgalagadi Transfrontier Park, the Kalahari Gemsbok and Gemsbok National Parks.
South Africa since the early 19th century in the Natal and Cape Provinces south of the Orange River, where the Cape lion population was eradicated by 1860.
A few decades later, lions in the Highveld north of the Orange River were also eradicated. In Transvaal, lions occurred historically in the Highveld as well, but were restricted to eastern Transvaal's Bushveld by the 1970s. Between 2000 and 2004, 34 lions were reintroduced to eight protected areas in the Eastern Cape Province, including Addo Elephant National Park. In Venetia Limpopo Nature Reserve, 18 lions were trophy hunted and 11 euthanized between 2005 and 2011.
Contemporary lion distribution and habitat quality in East and Southern Africa was assessed in 2005, and Lion Conservation Units (LCU) mapped. Between 2002 and 2012, educated guesses for size of populations in these LCUs ranged from 33,967 to 32,000 individuals. The LCUs Ruaha−Rungwa, Serengeti−Mara, Tsavo−Mkomazi and Selous in East Africa, as well as Luangwa, Kgalagadi, Okavango−Hwange, Mid−Zambezi, Niassa and Greater Limpopo in Southern Africa are currently considered lion strongholds. These LCUs host more than 500 individuals each, and the population trend is stable there as of 2012.

Lions usually hunt in groups and prey foremost on ungulates such as gemsbok (Oryx gazella), Cape buffalo (Syncerus caffer), blue wildebeest (Connochaetes taurinus), giraffe (Giraffa camelopardalis), common eland (Tragelaphus oryx), greater kudu (T. strepsiceros), nyala (T. angasii), roan antelope (Hippotragus equinus), sable antelope (H. niger), plains zebra (Equus quagga), bushpig (Potamochoerus larvatus), common warthog (Phacochoerus africanus), hartebeest (Alcephalus buselaphus), common tsessebe (Damaliscus lunatus), waterbuck (Kobus ellipsiprymnus), kob (K. kob) and Thomson's gazelle (Eudorcas thomsonii). Their prey is usually in the range of 190–550 kg (420–1,210 pounds). In the Serengeti National Park, lions were observed to also scavenge on carrion of animals that were killed by other predators, or died from natural causes. They kept a constant lookout for circling vultures, apparently being aware that vultures indicate a dead animal. Faeces of lions collected near waterholes in Hwange National Park also contained remains of climbing mice (Dendromus) and common mice (Mus).
In Botswana's Chobe National Park, lions also prey on young and subadult African bush elephants (Loxodonta africana). They successfully attacked 74 elephants between 1993 and 1996, of which 26 were older than nine years, and one bull over 15 years old. In October 2005, a pride of up to 30 lions killed eight African bush elephants that were between four and eleven years old.

In the 1890s, two Tsavo Man-Eaters attacked workers during the building of the Uganda Railway. Their skulls and skins are part of the zoological collection of the Field Museum of Natural History. The total number of people killed is unclear, but allegedly 135 people fell victim to these lions in less than a year before Colonel Patterson killed them.
The Njombe lions were a lion pride in Njombe in former Tanganyika, which are thought to have preyed on 1,500 to 2,000 people. They were killed by George Gilman Rushby.
Between 1990 and 2004, lions killed more than 560 people in Tanzania, mostly during harvest season in crop fields and in areas where natural prey is scarce.
In February 2018, lions killed a suspected poacher near Kruger National Park.
In February 2018, Kevin Richardson took three lions for a walk at Dinokeng Game Reserve in South Africa. A lioness pursued an impala for at least 2 km (1.2 mi), and killed a young woman near her car.
In July 2018, human remains were found in the lion enclosure of a privately owned reserve in South Africa. They were suspected to have been rhino poachers, as they had a high-powered rifle with a silencer, an axe and wire cutters.