Mammals had been around since the Triassic, but approximately 65 million years ago they moved into the ecosystme opening left by the dinosarus when they disappeared.

The saber-toothed cat family aolne was probably the most successful junting design ever created in nature, and as a family, they lasted longer than any dinosaur family did.위 두 문장 해석좀 부탁드릴께요:-)