In selecting breeds, the documentary follows three key criteria: geographic diversity, rarity and uniqueness, and the symbolic traits associated with the horse in the Chinese zodiac.

Director Mark Brownlow, who is known for the BBC nature documentaries Frozen Planet II and Blue Planet II, says via video that he was initially skeptical when invited to direct Horse Power two years ago.

"I'm used to blowing audiences away with groundbreaking stories and rarely seen animals, whether in the depths of our oceans or the frozen wilderness of Antarctica. So how could a film about a domestic animal possibly compete?" he says.

"But since we started filming Horse Power, I knew we were onto something special. Horses are often seen as the epitome of human dreams. By applying specialist wildlife film techniques — from drones to onboard cameras to ultra-high-speed cameras — we were able to capture their raw power, strength, breathtaking speed, and endurance," he adds.

Describing the science behind their hidden abilities as "mind-blowing", Brownlow continues: "The discovery that horses can read our emotional state from our expressions, their innate intuition, and their capacity to sync their heart rates with ours — it's extraordinary. But at its core, this is a human story."

One of the documentary's most captivating stories follows an 8-year-old girl being trained by her father, as she prepares to compete in an 18-kilometer endurance race with her Mongolian horse on the grasslands of the Inner Mongolia autonomous region.