Relax – no one is irradiating kitties. Adaptive radiation means that the first modern cats exploded through the Old World like particles shooting out of a radioactive rock.
It was a very slow explosion from a human perspective but incredibly fast in evolutionary terms.
Exact dates vary from researcher to researcher, but according to one well-known study, it happened like this (Johnson and others):
- Big-cats first appeared 10.8 Ma (million years ago).
- Bay cats and related felines: 9.4 Ma.
- The caracal lineage: 8.5 Ma.
- Ocelots and their relatives: 8 Ma.
- Lynxes: 7.2 Ma.
- The puma lineage (including cheetahs): 6.7 Ma.
- Leopard cats and close relatives: 6.2 Ma.
- The domestic cat lineage: 3.4 Ma.
Again, some researchers have found different dates (Nyakatura and Bininda-Emonds), but all studies show the rapid feline evolution.
Why so fast? No one knows, but perhaps it had something to do with a local mass extinction.
For unclear reasons, over ninety percent of Europe’s carnivorans disappeared between 8.5 and 2 Ma. (Werdelin and Turner)
The trigger could have been almost anything. There was a lot going on back then – scientists are still trying to sort it all out.
For instance, the world was cooling down and drying up. First Greenland and then the North Pole began to freeze up. West Antarctica developed its ice sheet. The Mediterranean Sea dried up for a while and the Sea of Japan became a freshwater lake. And then the Ice Ages began around 2.5 Ma. (For more details and examples, see Agustí and Antón; Govers; Hay and others; Krijgsman; Lyle and others; Prothero; Werdelin and Turner; and Zachos and others)
Things were changing everywhere, and animals had to adapt as best they could.
Cats landed on their feet, of course. The sabercat group of apex predators reorganized. Non-sabertooths, i.e., the ancestors of modern cats, had been very rare. Now their numbers began to increase.
Perhaps Felinae had room to expand. Anyway, the eight great lineages quickly came into existence, with beautiful results that are all around us today.
Featured image: Spain’s Cerro Batallones fossil dig, famous for many felid remains. PePeEfe. CC BY-SA 4.0.
Cited and uncited sources:
Agustí, J., and Antón, M. 2002. Mammoths, sabertooths, and hominids: 65 million years of mammalian evolution in Europe. New York and Chichester: Columbia University Press.
Antón, M. 2013. Sabertooth. Bloomington: Indiana University Press.
Cain, M. L.; Bowman, W. D.; and Hacker, S. D. 2014. Ecology. Sunderland, Massachusetts: Sinauer Associates.
Govers, R. 2009. Choking the Mediterranean to dehydration: The Messinian salinity crisis. Geology. 37 (2): 167170.
Hay, W. A., Soeding, E., DeConto, R. M., and Wold, C. N. 2002. The Late Cenozoic uplift climate change paradox. International Journal of Earth Science/(Geologische Rundschau). 91:746–774.
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