For 10 million years, cat-like predators vanished from North America's fossil record. Then they suddenly returned. Theories range from climate shifts to competition from bear-dogs that dominated the continent during this gap.
Rama, CC BY-SA 2.0 fr, via Wikimedia Commons
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.
💡Fun Facts
Nimravids are called "false saber-toothed cats" because they independently evolved long canine teeth, a feature that would reappear millions of years later in true cats like *Smilodon*.
Amphicyonids, the "bear-dogs," are not related to modern bears or dogs but belong to their own extinct family, Amphicyonidae.
The first true cat to end the gap, *Pseudaelurus*, was roughly the size of a modern cougar and is considered the ancestor of all later cats in North America.
The coordinates for this POI are within John Day Fossil Beds National Monument, which preserves a continuous and diverse Cenozoic fossil records.
The Thomas Condon Paleontology Center is open daily, 10:00 AM to 5:00 PM. Park trails and overlooks are open from sunrise to sunset.
Admission
Free
Accessibility
The visitor center is fully accessible. Many overlooks have paved, accessible pathways. Hiking trails are generally on uneven, natural surfaces characteristic of a high desert environment.
