An empty predatory niche
Imagine North America without a single cat, wild or otherwise. For about seven million years, that was the reality. The fossil record shows a continent devoid of feline predators during a period known as the "Cat Gap," which lasted from roughly 25 to 18.5 million years ago. This paleontological curiosity is especially visible in places like the John Day Fossil Beds, where the coordinates for this point of interest are located. These rock layers preserve a detailed timeline of life in the Cenozoic Era.
Before the gap, North America had many "false saber-toothed cats" called nimravids. These were not true cats of the family Felidae, but a separate, now-extinct family of carnivorans that evolved cat-like features through convergent evolution. Genera such as Hoplophoneus—a bobcat-sized predator with saber teeth—stalked the forests. Around 26 million years ago, these successful predators vanished from the continent, leaving a significant vacancy at the top of the food chain. Their disappearance marks the beginning of the Cat Gap.
When bear-dogs ruled
The empty niche did not stay vacant for long. With the cat-like nimravids gone, other carnivores became common. The most dominant among them were the amphicyonids, a group called "bear-dogs". These animals were not bears or dogs, but a distinct extinct family. Species like Amphicyon were formidable predators, some reaching the size of a modern brown bear, with a stocky build and powerful jaws. They became the apex predators across North America for millions of years.
The cause of the nimravids' extinction and the subsequent gap is a topic of scientific study. One leading theory points to environmental change. The climate was cooling, and dense forests were giving way to more open grasslands. This shift favored faster-running herbivores, which may have been difficult for the ambush-style nimravids to hunt. Another factor was likely intense competition from the newly diversified bear-dogs and other carnivores.
The long absence of cats finally ended around 18.5 million years ago with the arrival of true felids. A puma-sized cat named Pseudaelurus migrated from Asia to North America across the Bering land bridge. This species gave rise to all subsequent cat lineages on the continent, from the mighty saber-toothed Smilodon to the modern mountain lion.