Mutations as phenotypes, or visible characteristics, appear usually when there is too much inbreeding in a population, and such would certainly be the case around Chief’s Island. They can be virtually any physical characteristic: length of coat or mane, colour and colour pattern, body size, tail length - use your imagination.

I have to be honest here, and say that man - including the hunter - is not always the best selection pressure, but his presence is becoming more and more pronounced, and this is never a good thing. In the Okavango Delta, two of the factors that are cutting off the lion’s genetic flow are human encroachment, including poisoning the big cats as livestock predators, and the rising water levels. 

In one regard, the cessation of sport hunting has taken away any financial value lions may have had for the rural villagers, contributing to the poisonings and poaching. In 2013, commenting on Botswana’s ban on sport hunting, Simon Dures wrote, “Among many circles it would seem somewhat controversial for a dedicated conservation biologist and ecologist (possibly even a tree hugger) to be anti a ban of hunting, however in the context of Botswana; its economy, harsh landscape, cattle driven culture and increasing level of poaching, I strongly believe there are few viable alternatives that will successfully be able to manage these areas in a way that will allow the preservation of the wildlife that exists there now. Just to be clear I am not a hunter and do not see the appeal, however I am also not interested in debating the moral arguments of hunting, only in the preservation of biodiversity in the most realistic way possible”. As with the Cecil debacle in the Gwayi, there was a clear demarcation in philosophy between the Internet ‘conservationists’ and the real ones with regard to the implications of sport hunting.

 

In another vein, the trophy hunter has an obsession with the unusual, and a number of mutant specimens have been shot over the years simply because they would be an anomaly in the trophy room. Especially in the case of a maned lioness, where the hunter might not even pick up on the “ess” part until after the fact. A case in point: the famed Barbary lions.

There is a whole new topic to consider here, and that is the selective breeding for aberrant phenotypes just for the trophy room. It is a practice I personally consider meaningless and unethical, but it happens.

What about the so-called ‘black lions’? A number of photos have appeared on the Internet - enough  that Snopes has taken interest and labeled the stories false. And it is plain to see that the photos in question have been Photoshopped. But is there any reason why an aberrant black phenotype could not exist?

Probably the poster boys for black-maned lions were the Barbary lions, which are now extinct in the wild. Taxonomically, they were the same species as the modern African lion, but a different subspecies, and one from Constantine, Algeria was the type lion specimen first described by Linnaeus in 1758 (a ‘type’ specimen is the original specimen that was used to name a species or was later designated as the basis for that name). Being a different subspecies meant that they displayed different physical characteristics and occupied a distinct geographical range from that of the African lion. (Another factor which distinguishes different species from different subspecies is that members of subspecies may interbreed among each other and they will produce fertile offspring, whereas while it may be possible for members of different species to interbreed, their offspring will be infertile hybrids - this is what makes the separate geographical ranges important in defining subspecies). The last known Barbary lion was shot in the western Maghreb in 1942, though small groups may have survived in Morocco and Algeria until the 1960s. Therefore, there is now only one lion - Panthera leo. 

Back in the day, zoologists used to rely solely on visible physical characteristics as the sole criteria by which a subspecies would be recognised. With regard to lions, the characteristics included, but were not limited to, the colour and size of the animals’ manes. Modern researchers have identified nutrition, ambient temperature and testosterone levels as factors that influence the growth of the mane. Sub-Saharan lions kept in temperate climates, such as European or North American zoos, tend to develop bigger manes than wild African lions. Because the Barbary lions were found in the Atlas Mountains, it is supposed that this was a factor in their long dark manes. Today, of course, with modern DNA technology we can trace the genetic content responsible for particular characteristics, and in 2006 mitochondrial DNA - which is DNA that passes down from the female only and is therefore not altered by recombination with male DNA during reproduction - studies confirmed the genetic distinctness of the Barbary lion. 

But even among Barbary lions, no true black forms were ever recorded, though early explorers like Sir Henry Layard - who reported a black Persian lion in the 19th century - might be forgiven for using such terms based on large and dark manes.
Ranger was a lion born at the Glasgow Zoo in 1975. He sported a black chest and one black leg, which were believed to be mutations in cell pigmentation that are referred to as somatic mosaicism - somatic for the cellular level, and mosaicism for the mosaic pattern that results. Because the condition is a mutation of cells, and not a part of the animal’s genome it will likely not be passed on to subsequent generations by breeding. Ranger was a healthy lion who lived to the ripe old age of 22, though repeated attempts to mate him all ended in failure - perhaps as a result of his skin condition, he was also infertile, but I don’t know if this was ever confirmed. For some reason, after his death, blood tests proved inconclusive.

The whole point, I suppose, is that random mutations will continue to occur ad infinitum for all manner of characteristics and if environmental selection pressures determine that a particular variant is ‘new and improved’ and will give individuals exhibiting it a better chance for survival, it will gradually become incorporated into the genotype, and then the phenotype, for the species.

Perhaps the most pressing question, though, is what chances do Botswana’s wild lions have of future survival? In many ways, sport hunters were their most valiant guardians.