"In Prehistoric South America, starting out can be rough. Rougher still, staying alive. But for a plucky dinosaur like Thor, dodging hungry predators is a constant routine. When he grows up, he'll be one of the biggest dinosaurs alive. Still, wherever he goes, danger is never far behind. Stalking him is Loki, a predator with a deadly bite and the will to use it. An encounter with him is a brush with death. As time goes by, their paths will cross many times, in frightening and unexpected ways. For one remarkable dinosaur, a journey through life is a heart-pounding adventure. It all begins 94 million years ago, in Thor's egg."

On the edge of a forest in what would become Patagonia, a herd of Argentinosaurus is on the move.

"The arid plains echo with the sound of homecoming. These titans are called Argentinosaurus have been on the move for weeks. All of them are females. Generations of mothers, and daughters, and sisters, and aunts are headed to their nesting grounds, in a ritual as old as time."

The camera pans to a young female.

"This female, called Freya, is 20 years old. She's making this trip for the first time in her life. Laden with eggs, she's anxious and wary.

The camera pans out

"The journey hasn't been easy. As big as these dinosaurs are, predators are never far behind. The bigger the herd, the better the odds."

A dead Argentinosaurus lies nearby rotting.

"Still, many don't make it."

A pair of Skorpiovenator come out from the trees, drawn in by the smell of a free meal.

"At 20 feet long and 1 ton, Skorpiovenator is too small to be a threat to an adult Argentinosaurus, but the smell of a carcass is too good to pass up."

The Abelisaurid dives into the carrion.

"For scavengers like them, this is the best time of the year, but their lunch is about to have a rude interruption."

A Mapusaurus arrives.

"From something nastier, hungrier, and 5 times bigger. Mapusaurus. These carnivores often congregate here to hunt down the herds of Sauropods that pass through, but like virtually every land carnivore, she's powerless to resist the promise of a free meal."

The Mapusaurus roars at him, forcing the smaller predator to back off.

"Tha smaller predators know better than to challenge her for this meal and is wise to back down."


The herd finally arrive at the nesting site.

"The Sauropods' heyday in the Jurassic may be long over, but here in South America, they continue to thrive and have become the biggest animals ever to walk the earth. The herd has finally reached their destination; a flat river plain, larger than three football fields. Year after year? female Argentinosaurus come here to lay their eggs. Freya is back for the first time since she was born. Like all sauropods, her brains are not her strong suit, so she operates on instinct, but she's a good learner."

Freya gets too close to an older female, who immediately warns her off.

"Freya needs to find somewhere to lay her eggs, but she's not the first to arrive. These females are older and more experienced, and warn her off."

Freya then finds an unoccupied spot in the middle of the nesting ground.

"How about here? The ground here is firm, but warm and sandy."

Freya instinctively begins to dig and squats over it.

"Using the curved claws on her back feet, she digs a shallow mound and begins to lay her eggs. Heated by the sun, sand is the perfect natural incubator. By the end of the season, hundreds of females like her will lay thousands of eggs in clutches of 40, to secure the next generation and complete the cycle of life. For Freya and the other mothers, their work here is done. They all head back to their lush feeding grounds to the north, abandoning their offspring to their fate. Most of them will succumb to predators, but those females that make it to adulthood will return here someday to begin the cycle all over again."