Panthera leo : a species account

"Lion: the fiercest and most magnanimous of the four footed beasts" - Samuel Johnson's Dictionary of the English Language (1755)

Etymology

The lion’s name derives from the Latin Leo [1]; the ancient Greek λέων (leon) [2] with the Hebrew word lavi possibly also being related [3]. The generic component of its scientific designation, Panthera¸ is presumed to derive from Greek pan- (“all”) and ther (“beast”) but this may be folk etymology. The name came into English through the classical languages, but panther, is probably of East Asian origin meaning “the yellowish animal” [4]

Taxonomic Classification

The lion (Panthera leo) [5] is a mammal and second largest in the family Felidae, being slightly smaller than the tiger (Panthera tigris) [6]. The leopard (Panthera pardus) and the jaguar (Panthera onca) are the two other cats that make up the four "big cats" in the genus Panthera.

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Carnivora
Family: Felidae
Subfamily: Pantherinae
Genus: Panthera
Species: Panthera leo (P. leo)

Origin of a Species

Fossil evidence suggests that the earliest lion-like cat (P. l. fossilis) appeared at Laetoli in Tanzania in East Africa during the Late Pliocene (5.0–1.8 million years ago) [7].

In a pattern broadly resembling that of humans, lions migrated out of Africa during the Middle Pleistocene (800–100 thousand years ago - kyr) into Europe, Asia and North America extending as far south as Peru [8] – [9] and becoming the most widespread large terrestrial mammals during the Late Pleistocene (100–10 kyr) [7],[10].

Recent genetic studies have suggested that at least two distinct lineages of lion inhabited western Eurasia at the end of the Pleistocene: the Holarctic cave lion (P. l. spelaea), and the modern lion (P .l. leo) [11].

It has been suggested that a population bottleneck of the modern lion (ca. 55–200 kyr) allowed a single population of lions to replace older populations in Africa and south-western Eurasia [9].

This single origin replacement model of modern lion evolution provides a parallel to the ‘recent African origin’ model of human evolution (in comparison to the ‘multiregional evolution’ model), in which modern Homo sapiens evolved in Africa ca. 200 kyr and went on to replace hominids (e.g. the Neanderthals) elsewhere [8].

Sub-species Classification

Although modern lions genetically differ from leopards and tigers by 13.8% and 19.8%, respectively, differences from Holartic cave lions of 5 – 6% greatly exceed those among modern African lions (around 0 - 1.22%). Lions do show substantial variation within populations but only limited between population differences; like other wide-ranging large mammals [12].

Twenty-four sub-species classifications have been suggested for modern lions [13] based on external morphological differences in different geographical regions, such as; body size, coat thickness and colour, mane size and colouration as well as the extent of retention of juvenile spots into adulthood. However, recent mitochondrial DNA sequence variation analysis suggests that lions across Africa are the same and sub-Saharan lions should be considered a single sub-species Panthera leo leo [14]-[15].

Some even question the sub-species classification of the Asiatic lion, currently classified as P.l. persica, due to the limited genetic difference (1.1%) to African lions [12] – this difference being smaller than those found between human racial groups [16].

The IUCN currently recognizes two extant sub-species of lion [17]:

African lion Panthera leo leo (Linnaeus, 1758)
Asiatic lion Panthera leo persica (Meyer, 1826)

Status & Distribution

Historically, lions were distributed throughout the Mediterranean, the Near and Middle East as far as India, and all of Africa.

Lions were eliminated from their last European strongholds in Greece by 100 A.D. but survived until the 12th century in Palestine and the 20th century in Syria, Iran and Iraq [18]. The last reliable sighting of lion in Iran was in 1941 [19]. The Asiatic lion sub-species now exist only as a population of around 350 in and around the Gir Forest of north western India [20].

In Africa, lion were extinct in Tunisia in 1891 and in Algeria in 1893. The last “Barbary lion” of northern Africa was shot in 1920 although they may have survived in the High Atlas Mountains until the 1940s. The last wild “Cape lion” of South Africa was shot in 1850 [21].

Myers (1975) wrote, "Since 1950, their numbers may well have been cut in half, perhaps to as low as 200,000 in all or even less" [22]. Later, Myers (1984) wrote, "In light of evidence from all the main countries of its range, the lion has been undergoing decline in both range and numbers, often an accelerating decline, during the past two decades". [23].

In the early 1990s, IUCN/SSC Cat Specialist Group members made educated "guesstimates" of 30,000 to 100,000 for the African lion population [21].

Reduced numbers of lions are still present north of South Africa and Namibia and south of the equator. North of the equator they are found in a narrow belt south of the Sahara Desert on the western side and extending further south to link with the southern hemisphere population on the eastern side of the continent. “

Lions (Panthera leo) are listed as Convention of International Trade in Endangered Species (CITES) Appendix II and are regarded as ‘vulnerable’ by the International Union for the Conservation of Nature (IUCN) Red List [Version 3.1 2001].”

According to the IUCN “A species population reduction of approximately 30% is suspected over the past two decades (= approximately three lion generations).” [17]

“Two surveys have provided the first current estimates of the African lion population, with some ground-truthing. The African Lion Working Group, a network of lion specialists affiliated with the IUCN/SSC Cat Specialist Group, conducted a mail survey and compiled estimates of 100 known African lion populations. Not included were lion populations of known existence but unknown or un-estimated size. The ALWG African lion population estimate is 23,000, with a range of 16,500 - 30,000 [24].

The second survey was carried out by Philippe Chardonnet and sponsored by the International Foundation for the Conservation of Wildlife and Conservation Force. He also compiled estimates for 144 individual African lion populations, grouped into 36 largely isolated sub-populations. His methodology included extrapolation of estimates of known populations into areas where lion status was unknown, and his total figure is larger: 39,000 lions in Africa, with a range of 29,000 - 47,000 [25]

Declines in lion numbers appear to be continuing: Kenya was estimated to have more than 20,000 lions in 1963, dropping to 2,749 in 2002 and 1,970 in 2008 [26] representing a 28% decline in lion numbers over the past six years, indicating that lion populations in Kenya, and likely elsewhere, have yet to stabilize since the 2002 published estimates.

Pressures on land use from increasing human populations leading to continued fragmentation of the remaining suitable habitat coupled with indiscriminate killing in defence of life and livestock and prey base depletion are recognized as being the principle causes for the decline in lion populations [27]. Endemic and epidemic diseases are also likely to cause fluctuations in lion populations [28] - [32], although few populations have been evaluated for disease threats to date. In addition, unsustainable trophy hunting rates have also affected lion numbers in some areas [31]. For example, CITES trophy export numbers indicate that between 1992 and 2002, 1347 lion trophies were exported from Zimbabwe; maximum estimates from the 2002 surveys [25] indicate that 1686 lions of all ages remained.

Like lion numbers, habitat for lions is also suspected to have declined over recent times. Since the 1960s, the human population, land cultivation and numbers of livestock have steadily increased [25], [33]. Myers (1975) suggested lion range to total two million square miles or 5,178,000 km², remarking that extent was likely only about half of lion range in the 1950s [22]. The African Mammal Databank project estimated the lion’s potential area of occurrence at approximately 10 million km², while noting that much of the most suitable habitat is fragmented and unprotected. The most detailed range calculation is Chardonnet’s (2002) estimate of approximately three million km², with about half having some form of protection, from national park to hunting reserve. Overall, habitat for 18% of African lion populations is described currently as declining [25]

With few exceptions, lion populations now occur as isolated remnants with doubtful long-term viability. It is estimated that 43% of lions reside in only four populations in three countries and 45% of locations of lion prides have less than 70 animals [24].