You are in the scrublands of South Africa, 250 million years old.

The air in the early Triassic was thick, hot, and smelled of mud and ash. You were crawling through a rocky outcrop by the banks of a shallow, meandering river, seeking shade, when you found an opening in a narrow, sloping burrow.

You knelt down, the sand shifting under your hands, and tried to look inside. The entrance smelled earthy and slightly musky. You must have been too slow to back away.

A low-pitched, vibrating growl echoed from the dark tunnel—not a hiss, but a sound of raw defiance. Suddenly, a pair of sharp, intelligent eyes snapped open in the darkness. A shape, covered in brownish fur, rushes out of the hole, startling you to stumble backwards. The head that growls was about the size of a fox’s, with distinct long whiskers trembling with anger. This was no reptile.

It was a Thrinaxodon.

It wasn't fleeing; it was defending its home. The mammal-like reptile flared its lips at you, revealing trident-shaped, interlocking teeth designed for tearing. It looked like a cross between a weasel and a lizard, but its posture was high and alert, its muscular legs ready to pounce. It didn't hesitate, snapping its powerful jaws together—a sound that cut through the silence, and emitting a series of barks and growls to ward you off its burrow.