I think, therefore I harm
65 million years ago, the world was about to change. The dinosaurs, which had dominated the planet for 135 million years, were going extinct. Mammals were about to replace them as the leading class of the fauna. Among them, cats were about to assume a major role.
This 3-part series will let you discover how our beloved cats came to be. This article assumes no prior knowledge.
The first mammals appeared some 200 million years ago and founded the class Mammalia. The first mammals were small rodents, no larger than today’s rats. While a wide amount of large dinosaur fossils were recovered from that period, very few mammal fossils exist, making it difficult to pinpoint the exact time of their appearance and which one was the very first one. The scarcity of mammal fossils is explained by their very small size, in comparison to the dinosaurs which reigned at the time, making them less likely to survive and be found. However, it is generally admitted that mammals were probably in very small number because of the giant reptiles which competed for the same land. Nevertheless, by 80 million years ago mammals were found on every continents of the world, even America and Australia which were then already separated from Eurasia.
Fitting with the definition of a mammal, the first of these already produced milk, but they were not yet carrying their babies in their womb, and instead were still laying eggs. It is thought that lactation originally evolved as a mean to keep the eggs moist during incubation. Placental mammals, those who carried their young in a placenta, in their womb, until full term, would have appeared about 85 to 65 million years ago, while the dinosaurs had begun to decline.
Almost all of the dinosaurs disappeared from the surface of the planet about 65 million years ago. It is thought that a gigantic catastrophe occurred at that time, which changed many of the parameters of the earth, in particular temperature which decreased considerably by that time. Though there is still debate and proves are still missing as to the nature of the event, it is generally well accepted that a major meteorite hit our planet at that time, falling just East of what is now known as Mexico and the Caribbeans. A large number of species, other than the dinosaurs, also went extinct by the same period, including both fauna and flora. It would appear that few of these could adapt to the new environment left after the cataclysm.
As the dinosaurs deserted their land after about 135 million years of reign, the mammals, now ready to claim it, began a fast evolution, and within a period of just a few million years diversified and formed many of the mammal lineages known to us today. As the placental mammals covered the world, they were running into great troubles. While they still had a few predators left, they were mostly uncontrolled. Except for a few insectivores, mammals were predominantly herbivores, and if left unattended they would have depleted the flora quickly. But just in time, descending from insectivores, the first carnivores appeared some 62 millions years ago, forming the order Carnivora. First primitive, they soon evolved strong teeth and claws, characteristics of the order.
42 million years ago, the carnivores split into two suborders. Caniformia, which later comprised wolves, foxes, bears and dogs, and a number of other species which did not survive until today. The animals of this group tend to be social, forming packs (though bears made the exception). They are also opportunistic, choosing food other than meat when need be. In parallel, Feliformia is a meat only carnivore. Characterized by retractable claws and a generally lighter and more flexible body, this group gave rise to animals such as mongooses, meerkats, civets… and cats.
While it is clear that Feliformia branched away from the Caniformia at that time, the very first representative of the group has yet to be found in fossil records. However, the fact that both of these groups have a common ancestor explains many of the similarities found in both cats and dogs, such as their strong claws, strong canines and the pads under their paws. However, many differences were already making a distinction between the two groups. Only the Feliformia group have retractable claws, but more subtle is the fact that the members of the Feliformia are digitigrade, meaning that they walk on their toes, while the Caniformia are plantigrade, walking on the sole of their paws. These differences allowed the first group access to trees, while the members of the second group must remain on the ground. Among other differences, the Feliformia has teeth which are only appropriate for eating meat, while the other group has developed teeth able to ingest other ailments.
The Feliformia diversified and formed many species, all of which share a number of features in common with felines, but very few of these survived to this day. Animals of this group are often called false cats or cat likes, since they resemble felines but are not quite felines.
Proailurus spawned in Europe and Asia about 30 to 25 millions years ago. After years of debate, it is generally well accepted today as the first true cat, making it the first felid, a member of the new Felidae family. It was a rather small animal, not much larger than today’s domestic cat. It had a long body and a long tail, but short legs, which indicate that it probably stalked its prey from trees, like its ancestors. Its light body and retractable claws would have made it a good climber, but its short legs would not have made it a good runner. Despite this limitation, its large eyes, sharp teeth and strong claws probably made it a formidable predator.
Proailurus gave rise to Pseudaelurus about 20 million years ago. Its body was still elongated, though not as much, and its legs were still short but slightly less so. It probably was still using trees to catch its preys, because its characteristics probably did not make it a better runner.
Pseudaelurus spawned at least 4 species, ranging in size from a domestic cat to a cougar, but otherwise identical. The first true cat to ever enter North America, 18.5 million years ago, spawned even more species there. The largest of them was about the size of a cougar and none was smaller than a lynx. Some of them had slightly longer superior canines, leading thoughts toward the legendary saber-tooth.
Thanks to Dianda over at Cats & Co for providing the inspiration to this article.