Happy Anniversary, Planet Earth! Episode 2: “Mountains”

In the opening sequence of Planet Earth’s second episode, narrator David Attenborough reflects on humankind’s relationship with the highest parts of our planet:

“Some might think that by climbing a great mountain they have somehow conquered it. But we can only be visitors here.”

The idea that nature is “unconquerable” permeates throughout the entire Planet Earth series, but it is perhaps nowhere more apparent than in the “Mountains” episode.

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The Karakoram mountain range (Flickr: Maria Ly)

A decade after its original release, “Mountains” remains a dramatic and memorable viewing experience. The episode features breathtaking aerial photography of our planet’s greatest mountain ranges, intimate footage of some of the most rare, difficult to reach creatures in existence, and a score that suggests the viewer is about to embark on an epic journey. When you watch it, you can’t help but feel a little bit like Bilbo Baggins.

In this 10-year anniversary post we will celebrate the legacy of Planet Earth by reliving some of the most unforgettable moments in “Mountains.” We will also revisit several of the filming locations from the episode to find out how these iconic places have changed over the last decade.

Remarkable Mountains and Robust Mountaineers

During the episode we travel throughout many of the world’s major mountain ranges, focusing on the forces that shape these regions and the unique struggles of daily life for the plants and animals that live here. The alpine environment is incredibly volatile, and Attenborough touches on a number of factors that make it such a difficult place to inhabit.

Summertime blizzards strike without warning in Patagonia, pummeling guanacos and other residents with snow. Avalanches crash across the slopes of the American Rockies at over 400 kilometers per hour. Massive glaciers carve their way across the landscape- the Baltoro Glacier in Pakistan stretches 60 kilometers long, its path through the Karakoram mountain range visible from space.

With these near-cataclysmic forces at work, it’s a wonder anything survives here at all.

However, a number of organisms survive and even thrive here. From golden eagles to giant pandas, mountain lions to musk deer, red pandas to rhododendrons, a range of odd and interesting plants and animals have adapted to life in these high up places. And while the alpine environment is certainly a harsh place to live, one of the most interesting things about life here is that this harshness can sometimes come in handy for certain mountain inhabitants.

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The red panda, found throughout the Eastern Himalayas (Flickr: Cloudtail the Snow Leopard)

For example, in the Ethiopian Highlands we meet a troupe of monkeys known as geladas. The Ethiopian Highlands are certainly not an easy place to live; the region is so resource-poor that geladas must subsist almost entirely on grass (they are the only primates in the world to do so). However, the challenging terrain is also crucial to the geladas’ survival; the sheer cliffs provide refuge from predators that roam the Highlands, like Ethiopian wolves. It’s an example of how, paradoxically, some of the most inhospitable aspects of the environment can be exactly those that help an animal survive.

Similarly, in the Rocky Mountains we follow a female grizzly bear and her two cubs as they emerge from hibernation at the onset of spring. We learn that male grizzlies would likely kill the cubs if given the chance, but the female has built her den high up in the steep, snow covered cliffs, at an altitude where larger animals find it difficult to get around. This is another example of how the most challenging landscapes can sometimes be the safest. But in this case, the benefits to the mother and her cubs are temporary- there are not enough resources here to sustain the family indefinitely.

In showcasing the struggle to survive the alpine wilderness, “Mountains” also shows us footage of some phenomena that had never-before been captured on film.

In the Karakoram mountain range, we watch as a snow leopard stalks a young markhor along the jagged cliffs. The hunt culminates in a frantic chase, predator and prey moving down the mountain with an agility that is almost incomprehensible. This is the first recorded instance of a snow leopard on the hunt, and one of the most iconic moments in the Planet Earth series.

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Demoiselle cranes (Flickr: Alastair Rae)

In the final moments of the episode, we journey with 50,000 demoiselle cranes as they fly across the Himalayas during their annual migration. This is another never-before filmed event, and catching it on camera was hazardous. The Planet Earth crew filmed at record-breaking altitudes, nearly losing a crewmember to hypoxia.

The danger of the mountain environment is well captured in this behind-the-scenes anecdote. Humans are poorly suited to this setting, and, as Attenborough stated at the beginning of the episode, “we can only be visitors here.”

Ongoing Change in the Alpine Environment

The highest peaks featured in the “Mountains” episode are unconquerable, untamable, and (for the most part) uncolonizable for humans. But although we might not be able to colonize the mountain landscape, we are still affecting it.

With recent temperature increases due to climate change, glaciers in mountain ranges around the world are melting. The Andes have been hit particularly hard, with the massive Southern Patagonian Ice Field having receded by around six feet per year from 2000 to 2012. Seasonal runoff is a major source of drinking water for human populations downstream of glaciers, and the rapid depletion of reserves like these could have catastrophic effects for millions of people.

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The Perito Moreno Glacier, fed by the Southern Patagonian Ice field (Flickr: Jorge Láscar)

The mountain ranges of our planet are also important in shaping global weather patterns, and climate change in these regions could be causing an increase in extreme weather events. As explained in “Mountains,” the Himalayas play a role in creating summertime monsoons in southern Asia. Rising levels of atmospheric carbon dioxide appear to be causing increased rainfall in the region, with the potential to trigger devastating floods in highly populated areas.

Climate change seems even to be contributing to the crumbling of iconic peaks in the Alps, including the Matterhorn.

Alpine animals are also feeling the effects of human activity. Numerous animals featured in the “Mountains” episode have seen population declines in recent years. The Ethiopian wolf, snow leopard, giant panda, golden snub-nosed monkey, Himalayan musk deer, and red panda are all classified as “Endangered” on the IUCN Red List of Threatened Species. Common reasons for these declines include habitat destruction and fragmentation, human encroachment, disease, poaching, and competition with livestock.

Furthermore, some of the wildlife in “Mountains” probably would not even be found at such remarkable heights if it weren’t for us. The walia ibex (featured in the Ethiopian Highlands segment of the episode) used to range widely throughout the Semien Mountains. However, increasing human encroachment has decimated the species, and the remaining populations are currently restricted to marginal habitat at higher than typical altitudes. The extremes of the high mountain environment seem to have provided the walia ibex with some reprieve from our impact, for the time being. But with just 500 individuals left in the wild, the long-term effects of living in such a difficult place remain unclear.

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Walia ibex in the Semien Mountains (Flickr: Rod Waddington)

In short, many of the locations featured in “Mountains,” along with their flora and fauna, have been (and will likely continue to be) negatively impacted by human activity.

And yet, there are also some species whose plight has improved in recent years. The markhor in particular is a conservation success story, or at least the hopeful beginnings of one. When Planet Earth aired in 2006, the markhor was considered endangered. With fewer than 5,000 individuals in existence, populations were in rapid decline due primarily to excessive hunting. But thanks in large part to the efforts of local conservation organizations, markhor populations are currently stable, and the species’ IUCN status has improved to “Near Threatened.”

Ten years after the release of Planet Earth, the outlook for many of the species featured in “Mountains” is quite dismal. It is shocking to realize that we have had such a profound impact on places we can barely even reach. But stories like the markhor’s suggest that, with appropriate action, we may yet be able to preserve some aspects of these astonishing, unreachable places into the future.

Be sure to stick with us as we continue our celebration of Planet Earth’s 10-year anniversary! You can find our “From Pole to Pole” post here. Next week, we’re headed for “Fresh Water.”

Happy Anniversay, Planet Earth! (Pt 1 of 11)

Shots of Earth from space. The voice of a man you can’t see, but know you can trust.

One hundred years ago, there were one and a half billion people on earth. Now, over six billion crowd our fragile planet. But even so, there are still places barely touched by humanity.

So begins Planet Earth – a documentary series by the BBC and Sir David Attenborough that is so highly esteemed by us here at Nothing in Biology that we’re celebrating its 10 year anniversary by devoting the next 10 weeks to it. We’re reliving the majesty and checking in on some of our favorite places, organisms and phenomena. Essentially, we wondered “Where are they now?” Are any species better off than they were ten years ago? Have any gone extinct? How are we doing in terms of protecting the biodiversity hotspots?

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This series will take you to the last wildernesses and show you the planet and its wildlife as you have never seen them before.

We see breathtaking landscapes, terrifying heights, beautiful creatures and gruesome battles. We see millions of animals moving together and solitary animals rarely seen by humans. We see the highest peaks and the deepest depths. This series is the definition of awesome. Each week, we’ll embed full episodes and/or clips in the posts (the series is also on Netflix) for convenience but if you’re reading this and the links don’t work – definitely find another way to watch/re-watch/re-re-watch.


The first episode, From Pole To Pole is an overview episode that starts in Antarctica with the charismatic Emperor Penguin.

“Imagine our world without sun.”

As is true of many polar species, and especially true of species that use sea ice, there is much concern over the effects of global climate change on emperor penguins. Accordingly, some work has gone into assessing their current population sizes. Emperor penguins became the first species to have their population size estimated from space. The first recorded loss of an emperor penguin colony has been reported, and it is associated with rising local air temperatures and declining sea ice. Also, some modeling has been done, which suggests that global warming may result in a catastrophic decline of this species over the coming century.

On the organismal biology front, there has been tremendous interest in the emperor penguin’s ability to dive to extreme depths in search of prey. Recent work has established that they can dive as deep as 564m. Physiological research has shown that this ability is facilitated by an extreme slowing of heart rate (going from 85bp at rest to 6bpm at the end of very long dives) and the ability to survive blood oxygen levels so low that they would be “catastrophic” in many birds and mammals.

“A polar bear stirs.”

Next, we follow a mother polar bear and her two adorable cubs. Even more than emperor penguins, polar bears are a species of extreme concern when it comes to the effects of climate change. Their dependence on sea ice, and their fate as it declines has been the subject of much research and discussion, so I won’t go into it much here.

There are, however, other environmental concerns. It turns out that some pollutants from industrialized regions of the world find their way to parts of the arctic and reach high concentrations (PCBs, PBDEs). Some of these can be bioaccumulate, and because polar bears are at the top of the arctic food chain, there has been some research demonstrating high concentrations of these chemicals in their bodies and suggesting these could be a threat to the health of their populations, even effecting the bone density of male bears’ bacula. [Penises and penis bones are a long-standing interest of this blog].

Among novel research findings, in contrast to other bears, polar bears avoid bone density loss during hibernation. The mechanism may prove to be of medical importance to humans because bone loss with age, during prolonged bed rest and IN SPACE are problems.

“The immensity of the herd can only be properly appreciated from the air.”

Moving south across the arctic tundra, we next see the great Caribou migration.  As in, 3 million migrating caribou, the longest distance of any overland migration by any animal. Caribou are still very numerous in 2016, but declining and have been extirpated from some regions, while some other ungulates (e.g., Moose, White-tailed deer) are expanding northward into some of their former habitat. The mechanisms of decline are unclear, so much recent research has gone into trying to understand the interplay of climate change, direct anthropogenic alterations to habitat and predation.

“…a third of all the trees on earth.”

Boreal forests: low animal density, but massively important. They’re also massively threatened – by… you guessed it, climate change, but also by industrial resource extraction (logging and tar sands being major factors). Check out this map from globalforestwatch.org of forest loss in northern North America since 2006:

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Because boreal forests are so extensive and contain so much biomass, they hold huge amounts of carbon. As we all know, concentrations of carbon dioxide in the atmosphere are the primary driver of global climate change, so understanding the dynamics of these forests, their fate in a warming climate, and their role in carbon cycling through the atmosphere has been a major research priority.

“…at 50 degrees latitude, a radical transformation begins.”

Broad-leaved forest, complete with easy to digest food for herbivores. We’re treated to a relatively rapid montage through Eurasia and finally see a highlight of the episode – the rarest cat in the world, an Amur Leopard and her cub. In one of the bright spots for conservation in this episode, the number of this species has increased from 40 at the making of Planet Earth to around 70 today! HUZZAH!

“All animals, rare or common, ultimately depend for their energy on the sun.”

Next we see Japan’s Cherry Blossoms and some super cool time-lapse videos of seasonal change. A common theme in climate change research in northern latitudes is the ever earlier arrival of spring. Because Japan’s cherry blossoms are so culturally important, there are over 1200 years of data on the blooming of cherry trees available. Big surprise, these data reinforce that theme. Cherries in Japan are now blooming earlier than ever in recorded history.

A couple of bird species of note are also shown in this sequence: Baikal Teal and European Starling. Baikal teal are strongly recovering from a population crash in the mid-20th century, with some reports having their population increasing by up to several hundred thousand birds in the last decade. European starlings, however, are declining in Europe (almost 80% in Britain), though they remain an abundant invasive species in North America.

“There are parts of the world that have no seasons.”

The focus then moves to tropical forests, and some more really amazing footage, this time of birds of paradise in New Guinea. I mean – this footage is truly spectacular. There is not much work done on these birds (uncommon rainforest birds on New Guinea aren’t the most pliable study system). On the conservation front, they share with all spectacular rainforest creatures twin threats of poaching and habitat loss.

“Life in the oceans”

The episode then shifts focus to the oceans, and another iconic sequence: Great White Sharks feeding off the coast of South Africa. Life hasn’t gotten any easier for Great White Sharks in the last ten years, they are still hunted for teeth, fins and trophies and they are still a victim of bycatch. Oceans in general aren’t faring that well – suffering from overfishing, climate change and pollution. On the plus side, some conservation efforts in North America have led to an increase in population size in the eastern Pacific Ocean. Yay!

“…a search for water.”

Perhaps the most heartbreaking scene from the whole documentary follows a mother elephant and her baby in the Kalahari Desert, as they are separated from the herd and then separated from each other. The baby is last shown alone, following its mothers scent but in the wrong direction, to almost certain death. As you could probably guess, African Elephants are still in serious danger, with ivory poaching driving a global decline in their numbers (as many as tens of thousands a year). Saving these creatures requires international efforts – perhaps some more demonstrations like the destruction of ONE TON of ivory products that New York City held in Times Square last year.

“After four months of total darkness, the sun rises once more rises over Antarctica.”

We revisit the Antarctic as the episode ends – going Pole To Pole as the title episode promises. Be sure to come back next week when we revisit Episode 2: Mountains.
PS – There are now ~7.4 billion people crowding our fragile planet. And counting.

Noah contributed equally to this post.