You are in the forested grasslands of South America, 2 million years ago.

The wind was harsh on the Patagonian plains, carrying with it the scent of dust and frozen grasses. You had been navigating through the open scrub forest before the landscape opened into a vast, windy savannah. Through the thick, tall grass, you saw them—a herd of perhaps twenty, moving with a bizarre, rhythmic waddle.

They were Macrauchenia.

From a distance, they resembled giant, humpless camels or long-necked horses, but as you drew closer, the strangeness became overwhelming. They were massive, easily a ton each, standing roughly ten feet tall to the top of their small, alert heads. They walked on three-toed rhino feet, yet moved with a peculiar, high-strung agility.

The most stunning feature was its face. The nasal bones were retracted, sitting high on the forehead between the eyes, and from this strange opening extended—a fleshy, muscular sac on its snout that inflames and enlarges, producing a peculiar, whistling, yet squeaky, grunt, and trembling in the wind to presumably filter dust.

One of the animals turned its long, flexible neck to stare directly at you, its large eyes blinking slowly, looking like a biologically engineered horse with a head of a saiga antelope. It froze and grew tense. It didn't snort like a horse; it emitted a deep, rattling hiss from that high-mounted nasal opening. It stomped a three-toed foot, the sound sharp in the quiet afternoon.