Once upon a time, Disney was well known for its series of nature documentaries and television shows. (Sometimes for the worse: the 1958 Disney documentary White Wilderness famously featured a few dozen lemmings herded to their deaths to reinforce the myth of lemming mass suicide.) Though those documentaries and television shows have gone by the wayside, they now make a resurgence with Earth, an ambitious documentary and the first of a series planned by Disney’s new DisneyNature division.

Earth, directed by Alastair Fothergill and Mark Linfield, the team behind the award-winning television series Planet Earth, follows several families of animals over the span of approximately two years as they journey in search of food, water, and safety. The stories of those families are narrated by the familiar voice of James Earl Jones and accompanied by a sweeping, sometimes playful score.

It is a surprisingly effective mix. Earth hops from one family of animals to the next—a polar bear mother, her two cubs, and the father lost in a warming ice floe, an elephant mother and her son, a whale mother and her calf, other beasts and the predators that stalk them—moving from the north to the south pole. Mr. Jones’ voice and the score do much to add humanity to the animals’ struggles, but it’s a cold soul indeed that would not empathize with them even without the help.

Earth is a little light on facts, but facts aren’t really the point: this is a film about the high drama of simple survival, and drama abounds. For most of the documentary we empathize with the “prey,” animals that migrate sometimes thousands of miles and face peril at every turn. The fragile alliance between lions and elephants at a watering hole is particularly tense, and the showdown that degenerates into violence after night falls makes for genuinely suspenseful watching. These stakes are real.

But just when we might start to see predators as the “enemy,” Earth shifts our focus back to the father polar bear. His search for food in the icy wastes of the Arctic Circle takes him countless miles from home, and though his family’s survival means another animal must die, the father polar bear becomes something like a tragic hero. A simple truth underlines it all: Everybody has to eat.

Earth is skilled at this kind of recasting. Mr. Jones’ narration often takes a left-of-center view of the typical, calling baby ducklings “Earth’s newest recruits” and grass the “unsung hero” of the planet. It’s an effective device to make even the mundane seem mystical once again.

And then there is the cinematography. Earth is so relentlessly, majestically beautiful that it borders on overload—there are so very many sweeping vistas and massive flocks and herds of animals that sometimes it’s a relief when the directors shift focus to quieter portrayals of birds in tropical rainforests or lone lynxes stalking wintry forests.

Mr. Fothergill and Mr. Linfield carefully walk the line between the epic and the intimate, and the tension between the two strengthens Earth’s story of familial love and survival. Earth is sometimes heartbreaking to watch, but it is authentic, and its greatest triumph is to instill a simple sense of awe and appreciation for creation.