Origin - Page 1&2: The Early Development Of The Carnivores | 3: Origins Of The Tiger
Sabre-toothed cats and Dinictis:
When exactly the first true cat appeared is a subject of debate. Early cats were forest dwellers and there are rarely many fossilised remains found in this situation.
Two lineages of cat-like carnivores lived in North America about 40 million years ago. Experts were so convinced these were the first cats that they named them palaeofelids.
One branch was represented by Hoplophoneus, and the other by Dinictis which was similar to the modern serval. These early catlike animals shared one thing in common: they were sabre-toothed (Note: in the U.S.A, sabre is spelt as saber. The spelling used here is not incorrect, but is the 'Queens', or British, English).
It is now known that the sabre-toothed cats such as Smilodon were a case of parallel evolution, and are not related to our modern cat.
Approximately 20 million years ago, Pseudaelurus appeared on the scene. It was a medium-sized cat that hunted using an ambush technique. Pseudaelurus left a legacy in the form of the ocelot, kodkod, margay, tiger cat, pampas cat and Geoffroy's cat.
It is likely the ancestors of these animals crossed the Bering landbridge somewhere around five million years ago and then gradually made their way to South America.
years later the wildcats became established (Pallas cat, jungle
cat, European wildcat, African wildcat, black-footed cat and sand
cat). It is from these that the domestic cat was developed.
Fossil evidence indicates that early lions and cheetahs arose around 6 million years ago.
Leopards, tigers, and jaguars are relatively recent, having a history that goes back approximately 2 million years.
Evolution would see sabres disappear in favour of the canines found on the modern cat. As huge herbivores vanished, and faster prey like antelope appeared, the slow sabre-tooth cat was unable to keep up and the pantherines stepped into the breach.
These new predators needed extra speed, but they did not require the armoury of the sabre-tooth cats. Teeth like that, when used during a high speed attack, would only prove a disadvantage and science now knows that given the style of attack used by modern big cats, sabres would simply break.
With Thanks To T.M. Ponzetti (Photos 1, 3)