New DNA evidence is suggesting that lions in Africa’s Western and Central regions are more closely related genetically to the Asiatic lion than to their East and Southern African cousins.
A team of researchers from the Leiden Institute of Biology in the Netherlands conducted the study and published their results in the peer-reviewed Journal of Biogeography. The article, titled Genetic diversity, evolutionary history and implications for conservation of the lion (Panthera leo) in West and Central Africa, appeared in the journal’s July issue.
The team concluded that genetically, Western and Central lions resemble the Asiatic lion (Panthera leo persica) rather than the African lion (Panthera leo leo).
An in-depth knowledge of genetic variation within a species is crucial when planning effective strategies to manage wild populations as well as captive breeding stock, and this discovery will be of value to conservationists.
Africa's lions, while protected in many areas, are under threat. According to the Red List of the International Union for the Conservation of Nature, the total lion population has declined by about 30% over the past 20 years, and today a mere 1 700 individuals roam the West and Central African regions.
Lions face a diminishing habitat and food supply, as well as fragmentation of populations. They are also targeted by farmers and killed in retaliation for livestock theft, as well as by hunters seeking trophies. The Red List classifies West African lions as "regionally endangered".
During the study, researchers analysed the mitochondrial DNA of lions found across Africa and India.
They also tested the genetic material of extinct species such as the Barbary or Atlas lion, which roamed the Atlas Mountains of Morocco and became extinct in the wild in the 1920s. Specimens in captivity were also believed to have died out, but scientists have recently identified possible Barbary individuals in a number of circuses and zoos.
Although the differences in genetic make-up between African and Asiatic lions are not as marked as those found in different human racial groups, the research team maintains that the subspecies are distinct enough that one could distinguish one from the other if one knew what to look for.
African lions are bigger and heavier – the average male lion weighs in at a hefty 185 kg, and has a weight range between 150 kg and 230 kg. Asiatic males weigh between 160 kg and 190 kg, while the females of both subspecies weigh roughly the same.
Asiatic males have smaller, sparser manes which tend to leave their ears visible at all times. African males have fuller manes which are also generally lighter in colour. A lion’s mane gives other lions – both competitors and potential mating partners – an indication of the overall strength and fitness of that particular individual.
Pride and prey sizes also differ between the two subspecies. In Africa’s vast savannah, prides often consist of between four and six females and up to four males. The faster, more agile females generally do the hunting and the stronger, larger males patrol and defend their territory against trespassers.
The larger pride size offers an advantage in terms of hunting, as it means a greater chance of success when attempting to bring down bigger prey such as zebra or wildebeest.
Asiatic prides usually consist of two to four females, and males are often solitary. Since the Asiatic lion is confined to the Gir Forest in the Indian state of Gujarat, it’s restricted to smaller prey, most commonly the Chital deer which only weighs around 50 kg. This makes larger pride sizes unnecessary.
The genetic link between Western and Central African lions and their Asiatic counterparts can partly be attributed to natural phenomena such as Central Africa’s rain forest and the Rift Valley in East Africa. These structures have formed natural barriers which effectively inhibit lion populations from overlapping.
Another factor to consider is the region’s climatological history. Scientists estimate that the local population of lions became extinct during the Pleistocene period of 8 000 and 40 000 years ago, as a result of a drought. The survivors would have roamed far in search of food and water, and may have wandered into the Middle East and Asia.
Eventually some of these Middle Eastern animals may have recolonised the African region, which explains the close genetic relationship between these lions.