Dan Flores

Immense, hyperactive, short-faced bears twice the weight of a grizzly died in the asphalt. So did the enormous Miriam's teratorn, a Pleistocene bird of prey with a 10.5-foot wingspan. The remains span indigenous creatures spawned by continental evolution and migrants from Asia, some ancient to America, some recent arrivals.

Immense, hyperactive, short-faced bears twice the weight of a grizzly died in the asphalt. So did the enormous Miriam's teratorn, a Pleistocene bird of prey with a 10.5-foot wingspan. The remains span indigenous creatures spawned by continental evolution and migrants from Asia, some ancient to America, some recent arrivals.

Immense, hyperactive, short-faced bears twice the weight of a grizzly died in the asphalt. So did the enormous Miriam's teratorn, a Pleistocene bird of prey with a 10.5-foot wingspan. The remains span indigenous creatures spawned by continental evolution and migrants from Asia, some ancient to America, some recent arrivals.

The mammals and birds may seem alien or vaguely African, but in fact this bestiary was purely classically American, the America of the Pleistocene. The Rancho La Brea victims that left their bones and skulls encased in tar were once representatives of one of the grand ecologies of planet Earth.

The mammals and birds may seem alien or vaguely African, but in fact this bestiary was purely classically American, the America of the Pleistocene. The Rancho La Brea victims that left their bones and skulls encased in tar were once representatives of one of the grand ecologies of planet Earth.

The mammals and birds may seem alien or vaguely African, but in fact this bestiary was purely classically American, the America of the Pleistocene. The Rancho La Brea victims that left their bones and skulls encased in tar were once representatives of one of the grand ecologies of planet Earth.

This was a different America than most of us conjure when we imagine the continent Europeans found 500 years ago. But this La Brea world wasn't like the pre-Chixalube age of the dinosaurs absent of humans either. Late in the Pleistocene, our human forebears joined American ecologies as the newest predator here.

This was a different America than most of us conjure when we imagine the continent Europeans found 500 years ago. But this La Brea world wasn't like the pre-Chixalube age of the dinosaurs absent of humans either. Late in the Pleistocene, our human forebears joined American ecologies as the newest predator here.

This was a different America than most of us conjure when we imagine the continent Europeans found 500 years ago. But this La Brea world wasn't like the pre-Chixalube age of the dinosaurs absent of humans either. Late in the Pleistocene, our human forebears joined American ecologies as the newest predator here.

These first Americans lived their lives among La Brea creatures and created the first coast-to-coast human societies in American history. Their presence began to leave the continent and this rich aggregate of impressive animals forever changed.

These first Americans lived their lives among La Brea creatures and created the first coast-to-coast human societies in American history. Their presence began to leave the continent and this rich aggregate of impressive animals forever changed.

These first Americans lived their lives among La Brea creatures and created the first coast-to-coast human societies in American history. Their presence began to leave the continent and this rich aggregate of impressive animals forever changed.

The first time we became aware that humans were actually in America during the Pleistocene was barely a hundred years ago, and the place that happened was along the New Mexico-Colorado border. In the days following a flood in the dry Cimarron River,

The first time we became aware that humans were actually in America during the Pleistocene was barely a hundred years ago, and the place that happened was along the New Mexico-Colorado border. In the days following a flood in the dry Cimarron River,

The first time we became aware that humans were actually in America during the Pleistocene was barely a hundred years ago, and the place that happened was along the New Mexico-Colorado border. In the days following a flood in the dry Cimarron River,

An African-American cowboy named George McJunkin was riding through grassy parkland a few hundred yards below the rimrock of a miles-long mesa that extended eastward from the Rocky Mountains, checking for ranch fence lines damaged by the flood. Suddenly, McJunkin's horse braced, its hooves furrowing into foot-deep mud at the edge of a ragged scar floodwaters had cut into the slope below the mesa.

An African-American cowboy named George McJunkin was riding through grassy parkland a few hundred yards below the rimrock of a miles-long mesa that extended eastward from the Rocky Mountains, checking for ranch fence lines damaged by the flood. Suddenly, McJunkin's horse braced, its hooves furrowing into foot-deep mud at the edge of a ragged scar floodwaters had cut into the slope below the mesa.

An African-American cowboy named George McJunkin was riding through grassy parkland a few hundred yards below the rimrock of a miles-long mesa that extended eastward from the Rocky Mountains, checking for ranch fence lines damaged by the flood. Suddenly, McJunkin's horse braced, its hooves furrowing into foot-deep mud at the edge of a ragged scar floodwaters had cut into the slope below the mesa.

McJunkin leaned out of his saddle to peer into a fresh chasm sliced into the brown shale. What he saw changed the story of America forever. On a similar rainy August day in 2018, some 35 of us are stepping through the lush grass of that same slope as it angles up towards the rimrock of Johnson Mesa.

McJunkin leaned out of his saddle to peer into a fresh chasm sliced into the brown shale. What he saw changed the story of America forever. On a similar rainy August day in 2018, some 35 of us are stepping through the lush grass of that same slope as it angles up towards the rimrock of Johnson Mesa.