Programme commissioners were keen for a follow-up, so Alastair Fothergill decided that the Natural History Unit should repeat the formula with a series looking at the whole planet.

[8] In the United States, the series was promoted using "The Time Has Come" from trailer music company Epic Score,[9] composed by Gabriel Shadid and Tobias Marberger.

Actress and conservationist Sigourney Weaver was brought in to replace David Attenborough as narrator, as it was thought her familiarity to American audiences would attract more viewers.

On the nearby highlands of Simien Mountains, geladas (the only primate whose diet is almost entirely grass) inhabit precipitous slopes nearly five kilometres (3 mi) up, in troops that are 800-strong: the most numerous of their kind.

Grizzly bear cubs emerge from their den for the first time in the Rockies, while Himalayan inhabitants include rutting markhor and the rare snow leopard.

The episode ends with the flock of Demoiselle cranes flying across the Himalayan mountain peak to avoid the hostile air currents and predatory Golden eagles that threaten their migration.

In Japan, the water is inhabited by the biggest amphibian, the two-meter long giant salamander, while in the Northern Hemisphere, salmon undertake the largest freshwater migration, and are hunted en route by grizzly bears.

In this episode divers explore the otherworldly cenotes of the Yucatán Peninsula, appearing to be flying in water (because it is so clear), allowing viewers a glimpse of the hundreds of kilometers of caves that have already been mapped.

As the sun melts the ice, a glimpse of the Earth's potential future reveals a male polar bear that is unable to find a firm footing anywhere and has to resort to swimming—which he cannot do indefinitely.

Meanwhile, back in Antarctica, the eggs of the emperor penguins finally hatch while two adult Polar bear cubs from Arctic travels onward as they wander across vast track of frozen ocean independently from their mother.

In Outer Mongolia, a herd of Mongolian gazelle flee a bush fire and is forced to find new grazing, but grass self-repairs rapidly and soon reappears.

The insufficient water makes it an uneasy alliance and the latter gain the upper hand during the night when their hunger drives them to hunt and eventually kill one of the pachyderms.

Beyond the coral stretches the world of shifting sands, ocean dwellers, such as Gurnard, Jawfish, Green sea turtle, and Wonderpus octopus, are forced to cope with their environment through crucial camouflage and foraging where they have nowhere else hide.

In Shark Bay of Western Australia, Dugongs forage across the largest aquatic grassland eating tons of seagrasses a day while bottlenose dolphins perform their "hydroplane" in the shallowest waters to catch a meal.

Meanwhile in the desert shores of Bahrain, 100,000 Socotra cormorants rely on shamals that blow sand grains into the nearby Persian Gulf, transforming it into a rich fishing ground.

On a summer night on North America's east coast, periodical cicadas emerge en masse to mate—an event that occurs every seventeen years.

Beneath the dark seafloor, Deep sea creatures such as the sea spider filtering on marine snow, sawtooth eel gazing upward for prey shimmering from above the surface, Dumbo octopus roaming through the dark void, Vampire squid performing a special display of defense and predation, Monkfish luring prey for necessities, and the spider crab bid their time, awaiting carrion from above along with eels and giant isopods.

Nearer the surface, the currents that surround these seamounts force nutrients up from below and thus marine life around them is abundant, which allows the Nautilus to forage freely before retreat to the depth.

Thirty miles away, the shoal of squids jets upwards to the stream to hunt small fish and planktons while avoiding the pacific spotted dolphins as they use sonar to confuse their prey.

Off the Mexican coast, a large group of sailfish feed on another shoal of bait fish, changing colour to signal their intentions to each other, allowing them to coordinate their attack.

[27] Alongside the commissioning of the television series, BBC Worldwide and GreenLight Media secured financing for a US$15 million film version of Planet Earth.

[29] David Attenborough was replaced as narrator by high-profile actors: Patrick Stewart for the UK market and James Earl Jones for the United States.

The critical consensus reads "Planet Earth weaves innovative camera techniques and patient observation to deliver viewers an astounding glimpse of the world's perils and wonders, capturing jaw-dropping scenery and animals on both an epic and intimate scale.

The credentials of the filmmakers, the size of the production, a high-profile marketing campaign and a primetime BBC One timeslot all resulted in Planet Earth attracting large audiences when it debuted in the UK in March 2006.

[58][59] In February 2016, the BBC announced a six-part sequel had been commissioned, titled Planet Earth II, for release in late 2016, with Sir David Attenborough returning as narrator and presenter.

In the United States, it became the fastest and bestselling documentary DVD in Discovery Channel's history, and the high-definition (HD) discs generated US$3.2 million in sales in just two months.

The BBC Warner release retained David Attenborough's narration from the original British television broadcasts, but the Discovery Channel edition used the alternative Sigourney Weaver voice-over.

[66] Except for a small amount of extremely hard-to-obtain footage,[67] Planet Earth was filmed entirely in high-definition, and consequently became one of the first television series to take advantage of the new HD disc formats.

On the fifth disc, the bonus features from the standard-definition DVD set were replaced by two episodes from the BBC's Natural World series, "Desert Lions" and "Snow Leopard: Beyond the Myth", both also presented in high-definition.

[72] Four official tie-in volumes were published by BBC Books in 2006 and 2007: On 20 November 2006, a two-disc soundtrack CD was released with a compilation of the incidental music specially commissioned for Planet Earth.