Anoxic Conditions From Everest to Europa: Swamps, Fossils, Naked Mole Rats, and the Hunt for Extraterrestrial Life

Above elevations of 6500 meters (21,300 feet), most climbers tend to start using supplemental oxygen.  At altitudes higher than this, oxygen is spread so thin that humans can have a very tough time breathing.  Even people who come from sea level to my hometown of Boulder, Colorado at an elevation of 1,655 meters (5,430 feet) often get altitude sickness, and there's still a whole lot of altitude to go before you even get to Everest Base Camp.  Most birds don't fly as high as the summit of Mt. Everest, because most birds have no reason to fly that high.  However, for the bar-headed goose, the Himalayas form an unfortunate, but not impassable, barrier between their winter feeding grounds in India and their Tibetan nesting grounds.  These geese have been reported flying over some of the highest Himalayan peaks, and they're not the only ones that fly this high.  On November 29th, 1973, a Rüppell's griffon, a type of Old World vulture, collided with an airplane at an altitude of 11280 meters (37,000 feet).  By comparison, oxygen cylinders are recommended for sailplane pilots flying over 3660 meters (12,000 feet)!

Here we have a beautiful (and extraordinarily neat) size comparison and altitude chart of a number of things covered in the post, including the altitude of Denver, the summit of Mt. Everest, the upper extent of the range of the snow leopard, and the height at which the Rüppells griffon got sucked into the jet engine.  I've also thrown in some other helpful and fun things for comparison as well.

Part of what helps birds survive at altitudes that could kill a human is a series of air sacs that allow air to flow in one direction through the body of the bird.  In humans, the air we breath in and out travels back and forth along the same tubes.  In birds, as well as some of their close dinosaurian cousins, these air sacs would have have allowed the air to flow more efficiently through their bodies.  While this is simply one of many adaptations that can help birds fly at incredibly high altitudes, other animals have evolved other adaptations to assist in high altitude living.  Scientists have determined that changes in the genes EGLN1 and EPAS1 are linked with animals living in oxygen impoverished environments, such as the snow leopard, humans native to Tibet, and naked mole rats.  Naked mole rats live in underground colonies of 20-300 individuals, and are one of two species of mammal that can be classified as "eusocial," meaning that their colonies display a caste system (similar to the social structure seen in ant and termite colonies).  These underground colonies are poorly ventilated, which means that as the mole rats inhale oxygen and exhale carbon dioxide, CO2 concentrations can increase to levels that would be unsafe for humans.  Fortunately, naked mole rats are well adapted to breathing very little oxygen, and their brains seem incapable of registering pain upon contact with acids, which is thought to help them in these CO2 rich confines.  They also demonstrate similar changes in the aforementioned genes as snow leopards and the Tibetan people, indicating another adaptation to these low oxygen (or hypoxic) conditions.

A group of naked mole rats all huddled together at the Cheyenne Mountain Zoo in Colorado Springs, Colorado.  Look at all of that eusociality!

Although hypoxic conditions can bode ill for human climbers and gregarious colonial rodents, low oxygen conditions can be great for paleontologists.  When oxygen levels drop to nearly zero, anoxic conditions prevail, and bacterial decomposition of organic material is greatly reduced.  This can be a major factor when it comes to soft-tissue preservation, such as feathers and skin.  A FEW WEEKS AGO, we talked about several famous fossil sites called Lagerstätten (a German term meaning "mother lode"), that are set apart from other fossil deposits due to the quality and/or quantity of the fossils discovered there.  One of the most famous examples is the Cambrian-aged Burgess Shale in British Columbia, Canada.  Abrupt burial of the 500 million year old organisms, coupled with the anoxic conditions that prevailed at the bottom of this body of water, ensured that these soft-bodied organisms would be preserved in exquisite detail.

A drawing of Opabinia, one of the many creatures that inhabited the Cambrian aged Burgess Shale in British Columbia, Canada.  Photo Credit: Sam Lippincott

Why do swamps often have that rotten egg smell?  Believe it or not, the answer is closely related to what we've already been talking about!  Under hypoxic or anoxic conditions, bacteria that use oxygen (O2) sometimes have to make do with sulfur (S).  If you look at a periodic table, you can see that sulfur (element #16) is directly below oxygen (element #8).  In the periodic table, each group (or column) of elements has very similar chemical properties, which means each element will react in a similar fashion.*  For the bacteria that can't get enough oxygen, they will sometimes turn to its close cousin sulfur instead.  Below is the chemical formula for cellular respiration, which is what these bacteria do, as well as some of the cells in humans.  On the left, we have the inputs: glucose (C6H12O6), and oxygen (O2).  When we breath in air, we are bringing oxygen into our lungs, and we can get glucose from the foods we eat.  On the right of the arrow, we have the outputs: water (H20), carbon dioxide (CO2), and energy.  Remember how we talked about the CO2 concentrations in naked mole rat burrows?  CO2 is one of the products of respiration, and one that can be harmful in large doses.  Energy is another product of respiration, which is the fuel that cells need to do their job.  In places where there is less oxygen input (such as at the top of Mt. Everest or in a naked mole rat burrow), the cells don't get as much energy output, and they can't do their job as well.

Now, instead of having oxygen as one of the inputs of cellular respiration, let's try sticking oxygen's close cousin, sulfur, into the equation to see what will happen.  As you can see below, the glucose on the left of the equation remains unaffected, as does the carbon dioxide output on the right of the equation.  But instead of having water (H2O) as another one of the outputs, we now see a molecule with the formula H2S.  Instead of forming water (hydrogen oxide), we have now formed a closely related molecule, hydrogen sulfide.  In swamps, large amounts of organic material leads to lots of bacteria and bacterial decomposition, which in turn can lead to lots of the oxygen being used up in the water.  That's when these bacteria start using sulfur to make their energy, producing hydrogen sulfide, with that characteristic rotten egg smell.  Even with this sulfur replacement, sometimes the bacteria just can't keep up with the amount of vegetation that is deposited in the swamp, and the organic material builds up.  If the rate at which the vegetation accumulates exceeds the rate which the bacteria can decompose the vegetation, then you have coal formation potential sometime in the future.

Let's take this one step further.  In normal respiration, where oxygen is one of the inputs and water (H2O) is one of the outputs, carbon dioxide (CO2) is another one of the outputs.  If animals and bacteria keep using up oxygen and turning it into carbon dioxide, why haven't we run out of oxygen?  Will we run out one day?  Fortunately, for the time being, plants have got our back, by undergoing a process called photosynthesis.  Photosynthesis is almost the exact opposite of respiration: carbon dioxide and water are the inputs, and glucose and oxygen are the outputs.  However, unlike respiration, light is one of the inputs of photosynthesis.  In the 1700s, a man named Joseph Priestly did experiments in which he sealed a mouse in a jar, and waited to see what happened.  The mouse, as you could probably predict, suffocated and died.  It used up its oxygen to create energy (as well as carbon dioxide), and eventually ran out of oxygen.  (This is why it's important not to put animals into completely sealed jars with no airflow, as they will suffocate.)  However, if he put a plant into the same jar as the mouse, the mouse didn't suffocate.  We now know that is because, as the mouse used up the oxygen, creating carbon dioxide, the plant would use the carbon dioxide, ultimately creating more oxygen.

As you probably know, plants need light to survive, and as we mentioned before, that's because light is one of the inputs of photosynthesis.  No light, no photosynthesis.  No photosynthesis, your plant dies.  For many years, scientists assumed that all life on Earth was directly dependent on the Sun for its energy.  That is, until 1977, when scientists discovered entire communities of biological organisms living thousands of meters beneath the surface of the ocean, too far from any sunlight to undergo photosynthesis.  So what was going on?  How were these communities able to survive without access to the sunlight?

Hydrothermal vents are essentially underwater hot springs that form along tectonic boundaries thousands of meters beneath the surface of the ocean.  These underwater vents spew different compounds containing sulfur into the surrounding water, just like aboveground geysers do, too.  (If you have ever been to Yellowstone National Park, then you might even remember the rotten egg smell.)  Some bacteria that surround these vents are actually able to use these sulfur-containing compounds to create the energy needed to undergo a process similar to photosynthesis, called chemosynthesis (consult the equation below).  Chemosynthesis is very similar to photosynthesis, with a few key differences, the biggest difference being the sulfur reactions vs. sunlight as one of the inputs.  You can also see that, instead of having water (H2O) as an input like in photosynthesis, chemosynthesis instead uses hydrogen sulfide (H2S) as an input.  Then, instead of producing oxygen, the chemosynthetic organisms produce water and sulfur.  You can compare it to the oxygen-poor respiration equation that we talked about with the swamps, and see that it is similar to that equation as well, simply flipped around.

But that's not all.  Scientists have taken this idea a step (or rather, one giant leap) further.  The search for life on other planets thus far has yielded nothing, but that doesn't mean it's not there.  It is now realized that some of the factors that were once thought to limit the development of life, such as sunlight, might not be as crucial as we once thought, and the hydrothermal vent communities have been crucial in the maturation of these ideas.  Some scientists suspect that life could exist on Mars by using chemosynthesis, but a new candidate has been receiving an increasing amount of attention: one of Jupiter's moons, Europa.  Icier than the planet Hoth, Europa is now thought to have an ocean of liquid water up to 160 km (100 miles) deep surrounding the solid, rocky mantle, following the discovery of a magnetic field surrounding the moon, similar to the magnetic field that surrounds the Earth.

What keeps the liquid ocean of Europa from freezing solid?  Jupiter is pretty far from the Sun, and even Mars, which is much closer to both the Sun and the Earth than Jupiter is, has had its water frozen for millennia.  It's thought that the gravity exerted by the enormous mass of Jupiter continually pushes and pulls, or tidal stresses, on its moons, which keep the planets from becoming tectonically inactive, like Mars.  Io, another of Jupiter's moons slightly larger than our Moon, is the most geologically active body in our Solar System.  The tidal stresses from Jupiter exerted on Io apparently make Io's ground itself buckle up and down, similar to the tides we experience here on Earth, except that instead of water moving up and down 18 meters (60 feet), its solid ground moving up and down up to 100 meters (330 feet!)  It's these same tidal stresses that make Io so geologically and volcanically active that help keep Europa from freezing solid.  It has been hypothesized that the tidal flexing might also create hydrothermal vents on the bottom of Europa's oceans, and it shouldn't take too much thinking to realize what that might mean: the potential for extraterrestrial life!

*For example, we humans, as well as all known lifeforms, are carbon-based.  In science fiction, such as Star Trek and Transformers, you will often hear about "silicon-based lifeforms."  Why silicon, as opposed to any other element?  If you look at the periodic table, silicon is in the same group as carbon, and situated right beneath it, and therefore has very similar chemical properties as carbon.



Works Cited:

Eyes on Ears and Mouth on Toes

Despite the clever if misleading title, we will not be talking about mouths on toes today (although many creatures such as butterflies can taste with their feet).  I just said that to make it sound like the line from the classic song "Head, Shoulders, Knees and Toes" by Bob Dylan.  Instead, we are going to be talking about eyes on ears: eyespots, at least!

A picture of one of the Amur tigers at the Denver Zoo.  See those white bars surrounded by dark fur on the ears of the cat?  Those are the topic of today's discussion.

On the cover of the August/September issue of the National Wildlife magazine, there was a picture of a drinking bobcat, its ears folded back in the posture that some refer to as "airplane ears."  On both of its ears were two white bars that made the ears look a lot like eyes.  I never really paid attention to this pattern on the coat, but once my friend Aidan Cook pointed it out, it got the proverbial gears going.  I remembered that servals also had the eyespot-like patterns as well, but did other cats?  Turns out a lot of them do, with just a few shared throughout the post.  Notice how defined the eyespot is in both the bobcat (top) and the serval, below.

To learn more, I consulted my "Wild Cats of the World" book by Mel and Fiona Sunquist.  The authors state that many cats have this pattern on their ears, "almost as many species" have the ear eyespots that are "poorly defined or absent."  One of the many examples that they include is the lion.  As you can see in the pictures below, lions do have this pattern to a certain degree, but nowhere near as derived as in the serval or the bobcat.  Below we have pictures of a young adult male lion, two of females, and one of a cub, and you can see that none of them have a very well defined eyespot.

Mountain lions also generally don't have it as well defined.  It seems like some mountain lions really don't have that much black on their ears at all, and some have a higher degree of black and white.  Presumably, whatever the function the eyespot serves in other species, it is not as important for the mountain lion, and natural selection therefore does not favor it highly one way or another.

It's a little tough to tell in the picture below, but the sand cat is another one of those cats that has a poorly defined eyespot.

Cheetahs also don't have terribly well defined eyespots.

Yet another cat that does not have very well defined eyespots, the ever fantastic Pallas cat!

I thought I had read somewhere that the eyespots served to help communicate between individuals when they were hunting.  This doesn't make that much sense, though, because most cats are solitary individuals, with the main exception being lions, and we already noted that their eyespots are not quite as specialized.  The Sunquists state in their book that the exact function of the eyespots is unknown, although some scientists believe that they serve as a "follow me" signal to their young, which "may be especially important in low-light conditions."  I assumed that this might mean that the young cats wouldn't have the eyespots, but this is clearly not true, as you can see the photograph of Sochi, the new male Amur leopard cub at the Denver Zoo.  There, you can see that Sochi (named after the Russian city that is holding this years Olympics) also has the ear spots.  So while this doesn't necessarily support the idea of a "follow me" signal to the young, it doesn't really not support it either: it's just something interesting that I wanted to point out.

We already talked about how tigers have a pretty well developed eyespot, but here are two more pictures of tigers to drive the point home.

I can't remember for certain if the picture below was a bobcat or a lynx, but I am pretty certain it is a bobcat, looking at the size of the feet.  (Lynx spend a lot more time in the snow, and therefore have larger feet, a snowshoe-like adaptation to keep them from sinking in.)  This cat, one of many at the Wild Animal Sanctuary, seems to have much smaller feet in proportion to the rest of the body.  Regardless, you can see the well defined eyespots.

The snow leopard, one of my favorite cats, has well defined eyespots as well, which you can kind of see in both of these pictures.

Photo Credit: Masaki Kleinkopf 

The fishing cat is another cat that has these well defined eyespots.

And finally, the Canadian lynx, much like its bobcat relative, also has pretty well defined eyespots!

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An Amur Leopard Upchucks

On Saturday, January 26th, my father and I drove down to Colorado Springs to see a few of my friends perform in the Colorado All State Jazz Band.  Before the concert, we met up with my grandma and grandpa, and went up to the Cheyenne Mountain Zoo for an hour or so.  We saw a few cool things, all of which I will share with you in the next post, but this post I wanted to devote to the "Critically Endangered" sub-species of the leopard, the elusive and mysterious Amur leopard.  Fewer than thirty of these amazing creatures are thought to be alive in the wilds of southeastern Russia and northeastern China, in the Primorye region.  Poachers have taken an immense toll on the numbers of this cat, as its pelt is highly prized.  Like that of the snow leopard, another fairly large cat that also lives in a very cold, harsh environment, the Amur leopard has a very soft and, for lack of a better term, floofy, coat.

The Amur leopard prior to its little....episode.

Since the number of people who see an Amur leopard in the wild per year could almost certainly be counted on one hand, you are very unlikely to see this animal lose its lunch.  For that, you would have to go to a zoo. Now, don't get me wrong, we didn't go to the zoo just to see animals throw up, but it was definitely an interesting addition to our day!  I do hope that the poor animal is feeling better, though.  If you want to see the video of the animal barfing, click on the link below.  It's not actually as gross as it sounds, trust me!  Also, please enjoy some pictures of the beautiful cat PRIOR to its cookie tossing.  

The leopard recovers after it loses its cool

Your Dog May Be Dumb, But It's Brain Has More Folds Than a Cat's

When it comes to the anatomy of the brain, the more folds it has, the better.  This is because the folds create more surface area on the brain, which in turn creates more area for neurons to be, which in turn allows for more storing of information.  A month or two ago in my Psychology class, we briefly touched upon the brains of other animals.  I particularly remember the brains of the domestic dog and the domestic cat.  Even though it often seems, especially in my house, that my cat is a whole lot smarter than my dog, a quick look at the brains of both pets indicates otherwise.  The cats brain is pretty smooth in comparison to the brain of the dog.  If you think about the major differences between these two carnivores, one obvious difference sticks out like a football player in a group of people going to see the Hobbit premiere this weekend who are fully decked out in Lord of the Rings gear and are all Hobbit-sized: dogs are social creatures, while cats have a much more limited social capacity.  This probably helps to explain why your cat will suddenly and randomly bite you after you have been so lovingly petting her in your lap while she is purring.  They just don't know how to handle that much attention!  They also don't have any built-in social protocol.  Think about a socially awkward child: the situation is similar, except for the child it is simply that they had a different upbringing and not usually a matter of brain size.  Or maybe cats are just insane.

Anyways, as you can see by comparing the brains of the cat (above) and the dog (below), the dog has many more folds in its brain.  This makes sense, because the social interaction component would need more brain area to successfully function.

REAL FAST:  BELOW IS A HUMAN BRAIN FOR COMPARISON.

So with this in mind, it would make sense that the brain of the lion would be larger than, say, the brain of the leopard, now, wouldn't it?  Since the lion is a social animal, you would definitely think that.  This doesn't seem to be the case, however.  I did a little digging and couldn't really come up with much, but if I had to hazard a guess I would say its because the lion has the pride to fall back upon, so they don't necessarily need to be smart ALL of the time.  Also, leopards are extremely acrobatic, and spend a lot of time in the trees.  I suspect that this might also affect things, but I guess I don't know!  When I attempted to research it, literally all I could find was a bunch of Internet people comparing operating systems (?) called "Lion" and "Snow Leopard." 

Next we are going to compare the brains of the wolf and the red fox.  As you can see below, here our "Social Interaction=Big Brain" hypothesis is sound.  Not only does the wolf have a lot more folds in its brain, you can also see that the canyons created by the folds themselves are much, much deeper, which creates more surface area. 

Finally, let us compare the brains of the polar bear and the black bear.  HOLY.  COW.  As you can quite clearly see in the pictures below, the polar bear has MUCH more surface area on its brain than the black bear.  Now if you think about it, the environment that the polar bear is forced to survive in is much harsher than that of the black bear.  IN OUR POST ABOUT THE POLAR BEAR, we featured a video IN WHICH THE POLAR BEARS ARE PLAYING WITH SPY CAMERAS.  As the narrator points out, the curiosity of the polar bears is their "best hope for the future."  In their ever-changing world of ice and snow, which is now unfortunately melting, this curiosity is often what helps them survive the long, lean summers after the melting of the pack-ice, as well as the long, dark and cold winters.  Hopefully this brain power will be enough to sustain their populations in the future!

The Making of Planet Earth: The Snow Leopard

It was obviously not an easy feat for BBC to get all of the footage that they needed for their fantastic television series "Planet Earth," narrated by the equally fantastic David Attenborough.  Clearly, some segments would be easier to film than others.  One of the goals of "Planet Earth" was to get as much unique, never-before-filmed events and creatures, which would clearly make things a bit more difficult.  Below are listed some of the scenes that had apparently never been seen before on television.

1. The oceanic whitetip shark.
2. A piranha feeding frenzy, being filmed while the cameraman was actually in the water.
3. Arctic wolf hunt filmed from a helicopter.
4. Starving lions attacking and killing an elephant in the dead of night.
5.  Lechuguilla Cave in New Mexico, U.S.
6. Amur leopard mother and cub in the Primorye region of Russia.
7. Bactrian camels in the Gobi desert in Mongolia eating snow to keep from getting dehydrated.
8. "The highest-ever aerial footage of Mount Everest and the Karakoram."
9. African wild dog hunt filmed from a helicopter.

And, finally, the subject of today's post:

    10. A snow leopard hunting a markhor in Pakistan.

The snow leopards are another one of my favorite animals, but due to their elusive nature, they are very difficult to capture on film.  Much more difficult than they are for poachers to capture them, anyhow.  Hunting in large part for their fur has greatly reduced the wild population, forcing the IUCN to list them as "Endangered."

Due to their elusive nature, and their difficulty to film, the "Story of the Snow Leopard," if you will, proved to be a most excellent candidate for the "Planet Earth Diaries" (which I generally refer to on this blog as "The Making of Planet Earth."  For the DVD release, a ten minute or so long "making of" feature was included, highlighting the difficulties of each shoot.  Below is the list of the episodes of Planet Earth, and what their respective "Making Of" featurettes talk about.

The chart.  The Shallow Seas episode, with the
Planet Earth Diaries about the great white shark hunts, is filmed by Big Car Diary co-host Simon King.

When it came to filming the snow leopard, the makers of "Planet Earth" first turned to veteran cameraman Doug Allan, the same man who filmed the polar bears.  But after a few months of fruitless searching (in Nepal, I believe), all he had to show for his work were a few long distance shots, too far away to be of much use.  There were plenty of signs of the snow leopard being around, however.  One of my favorite things to hear from the entire "Planet Earth" series came from this predicament.  The film crew would track the snow leopard by following its footprints in the snow, in the hopes of getting close enough to learn more, or to even film it.  However, they would follow the tracks in a large circle, until they were seeing signs of human footprints too: their own.  The snow leopards were following them!

"Planet Earth" then decided to film along the Pakistan/Afghanistan border, but were not allowed to, as the search for Al-Qaeda was taking place there, and only news crews were allowed in.  One year later, however, the "Planet Earth" crew were granted access, in December of 2004.  Below is a link to part two of the "Planet Earth Diaries" about the snow leopard.  The first part was unfortunately taken off of youtube, but anyways, here is the second part.

Planet Earth Diaries: Snow Leopard Quest Part 2

Below is another fascinating video of the snow leopard: the first ever snow leopard/markhor hunt recorded on film.  SPOILER ALERT: and don't you worry you animal lovers out there; the video has a happy ending for the markhor, but not so for the snow leopard.

First Ever Snow Leopard/Markhor Hunt

Redington Beach on Dwellable

The Making of Planet Earth: The Polar Bear

First of all, don't forget to scroll down and look at today's official post, about the three-toed sloth! 

I almost forgot to tell you all about another very interesting video clip about the polar bear, from "The Making of Planet Earth."  The clip below, narrated by David Attenborough, features the challenges that the main cameraman Doug Allan, aided by his field assistant Jason Roberts, came up against when it came to filming the polar bears in Norway.  Not only is the video quite interesting, it gets amusing towards the end, as well!

Filming the Polar Bears

Below is a picture of cameraman Doug Allan.  In the picture below, he is staked out, attempting to film the snow leopard, one of my absolute favorite animals.  This elusive cat proved quite difficult to film, and, hopefully, sometime in the next few weeks I can talk about the difficulties the crew of Planet Earth encountered when it came to filming the snow leopard in the wild.

Acrobatic Felines: The Caracal

(Almost) everybody loves cats!  Not only the domestic kitties, but wild cats too, like the speedy cheetah, the social lion, and the elusive snow leopard, among others.  But most people don't know that there are all sorts of different cats, and thirty-six generally accepted species of cats!  Many have numerous sub-species as well, the leopard having eight or nine all by itself.

Today, I am going to introduce you to one of my absolute favorite wild cats: the caracal, which is fortunately labeled "Least Concern" by the IUCN.  The caracal is found all over Africa, pretty much except in the rainforests and the deserts, as you can see in the map below.  The caracal is also found in various non-African countries, such as Israel, Iran, Arabia, Jordan, Pakistan, and India.

I am not going to do a lot of talking (which is not normal, believe me), as words can't really do justice to what this cat can do.  So just click the link below, and be amazed.  (I actually have never watched this video with the audio on, so I don't even know what he is saying, because I think that the audio would simply detract from the video.  Enjoy!)

http://www.youtube.com/watch?v=4dCXK6KhkTw