It’s been a while since I wrote a more “biologically themed” post so today’s article is going to explore the origins of lions. Well, I say today….. It’s actually 4:15am and I’m still sat in my university library for what feels like the 100th night in a row trying to finish my final year project, I’ll let you guess how that’s going!
So, lions. Perhaps the most famous of the big cats. I doubt you could find many people in the world who haven’t heard of them yet despite their fame and notability, lions have seen a 30-50% decline in numbers over the last few decades. It’s so difficult to put those kinds of numbers in context , that’s well over 200,000 lions we’ve lost over the last 30 or 40 years, the same as the population of a small city! One of my first posts was a short piece about the origins and evolution of big cats so today I’m going to zoom in on lions with the hope of finding out some more about their evolutionary history. It’s my eventual aim to cover the evolution of each of the big cats post by post, and I was going to start with leopards, however I feel this blog has been a bit “lion light” over the last few weeks so I’ve decided they’ll kick things off today.
A 2014 study (I’ll leave a link at the bottom of the page) analysing genetic data from both living lions and museum specimens, including the now extinct Barbary Lion concluded that the most recent common ancestor of modern lions lived around 124,000 years ago, the late Pleistocene. Plenty of notable events happened in the Pleistocene, from the begining of the extinction of famous megafauna such as Woolly Mammoth’s and Sabre-tooth cats, evolution of Homo sapiens and 11 major glaciations. The continents were pretty much all in the places as we still see them today, which makes it slightly easier to visualize how lions evolved, and then expanded to cover Africa, the Middle East and Asia.
Lion’s had one of the greatest historical ranges for any large mammal in the late Pleistocene. Ranging from Sub-Saharan Africa all the way through to Central America lions were once plentiful across their range, however like many large apex predators, hunting and persecution have seen them driven out of many habitats where they once resided. Now, lions are only found in West, Central and Southern Africa and the Gir Forest of northwestern India.
So, how did they evolve and where did the first lions come from?
Well, the aforementioned study, after analysis of mitochondrial DNA concluded that lions (well, the first species Panthera leo) first appeared in eastern and southern Africa, separated from other lion populations by the expanding tropical rainforest of the late Pleistocene. This is a great example of allopatric speciation, where, biological populations of the same species become isolated from one another in a way that prevents the exchange of genes, in this case through sexual reproduction. Interestingly, despite the reduction of tropical rainforest since the late Pleistocene, those genetic differences can still be found in the African lion populations of today.
Following the creation of a barrier (tropical rainforest) between the lions of south and east and north and west, the expansion of the Sahara desert around 51,000 years ago created another geographical barrier between West and North African lions. No longer able to mix, West African lions periodically moved into Central Africa during periods of rainforest reduction (most likely due to climate) however they were now geographically isolated from their North African relatives.
So to recap where we’ve come so far
- First, lions from South and East Africa were separated from North and West African lions by the tropical rainforests of the late Pleistocene around 124,000 years ago
- Next, as global temperatures increased, precipitation decreased and the Sahara desert expanded, another geographical barrier formed between the lions of north and west Africa around 51,000 year ago
So I guess that goes some way to explaining how we’ve come have numerous different species of lion in Africa, however the study also highlighted how lions moved across into Asia not once, but twice in the last 21,000 years. The study says that until 2014 (when it was undertaken) obtaining DNA evidence to support the hypothesis that lions moved from Africa to India ~21,000 years ago was impossible, however the new availability of ancient DNA allowed for scientific evidence to support the hypothesis.
Further to their initial forays into Asia 21,000 years ago, lions expanded once again from Africa, this time into the Middle East approximately 5000 years ago reaching as far as modern day Iran, before the advent of firearms and surges in the popularity of hunting caused these Middle Eastern lions to become extinct. Until the late 19th century lions were even found as far east as Turkey!
Now that we’ve established the origins and evolutionary history of lions, I just want to touch upon another interesting find unearthed by the same study, the fact that all these cycles of lion “expansion” (or I suppose geographical barrier creation might be the more correct term) coincided with climactic shifts during the late Pleistocene and Holocene. The study found that during periods of high humidity such as Marine Isotope stage 5 (120-110 thousand years ago), tropical rainforests grew and expanded, and this time frame correlates well with the first period of lion diversification. Another humid marine isotope stage (MIS 3) occurred between 50 and 45 thousand years ago, just 1000 years after a period of high aridity caused the expansion of the Sahara desert and the separation of West and North African lions.
These cycles of aridity/humidity generally correlate with the different periods of lion diversification which lead the study to suggest that in part, the evolution of lions was influenced by climactic changes, something which certainly seems feasible.
In addition, although I won’t go into it in this post because my dissertation deadline is fast approaching, the study also goes into more detail explaining what geographical barriers have kept these lion populations apart and unable to mix with each other, including features such as the Nile, and Niger rivers. I’ll leave a link to the study at the bottom of this post if you’re interested in finding out more!
I hope you’ve enjoyed reading about the origins of lions! I always think it’s great to learn about something new, which I perhaps hadn’t considered in much detail before. In my next post I plan to have a closer look at tiger poaching (not a pleasant topic I know) and attempt to find out what’s being done to combat what is one of the biggest threats facing the conservation of tigers.
**If you’re not part of university or research institution you may not be able to read the whole paper. I’m not sure about this as I’m currently at University so am accessing it through that account. If you can’t read the whole paper, and would like to, I’ve downloaded a copy and would be more than happy to email it across, just let me know! You can contact me at firstname.lastname@example.org or @pantherablog on twitter **