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:

Chiidax the Northern Fur Seal and the Evolution of the Otariids

Late last year, the New England Aquarium in Boston, Massachusetts received Chiidax, an orphaned northern fur seal (Callorhinus ursinus).  However, it was last July that Alaska SeaLife Center first took in Chiidax, after he was left outside the Alaska Department of Fish and Game offices.  A note which was included on the outside of the box that the pup came in said that the pup's mother had died while she was giving birth.  Notice how in the first two pictures of Chiidax below, the pup is covered in an all black coat, a mark of his young age.

After the pups are weaned at around four months old, they molt into their next coat, the cream and brown color of the young juvenile northern fur seal.  Look for those in these next four pictures, taken sometime last fall.  The post on ZooBorns (read that HERE) doesn't say exactly when the pictures were taken, but given that the post was published late last November, these last photos were presumably taken around then.  

When the first post on Chiidax was written on November 23rd of 2013, he weighed 18 pounds, but when he's full grown, he will definitely be a bit bigger: the males, or bulls, of the species can weigh nearly 600 pounds, which is several times more than the females weigh!  The males have to be so large because they create harems of thirty to forty females, and defend them from other males.  The seals are native to the Pacific Coast of the United States, as well as the coast of the Bering Sea in Canada, Alaska, and Russia.  

The last report on Chiidax was in late December, on the 29th.  Below are several pictures that were shared then.  You can see how smooth he looks, and how perfectly adapted for a life beneath the waves this creature is!  

The northern fur seal is the sole extant member of the genus Callorhinus, but there is also a fossil species of Callorhinus.  C. gilmorei is known from the Pliocene Epoch of southern California and Mexico, as you can see in this paper HERE.  Other sources cite another paper, linked HERE, as stating that this genus is also known from Japan, but I was unwilling to pay the fee to read the paper, so that fact remains unconfirmed.  If you have a subscription to this online journal, let me know what you find!

According to the first paper, the eared seals, or the members of the family Otariidae, can be traced back at least to the Mid to Late Miocene Epoch, approximately 11-12 MYA in California, in the form of Pithanotaria starri.  Another taxon, Thalassoleon mexicanus, is known from Mexico during the Late Miocene, approximately 5-8 MYA.  The authors of the paper suggest that between 5 MYA and today, between our time and the time of Thalassoleon, was when fur seal diversification took off, resulting in the eight extant species of Arctocephalus and the extant Callorhinus ursinus, which includes little Chiidax!  The genus Arctocephalus, along with the genus Callorhinus, comprise the extant members of the eared fur seals.  The writers of the paper also suspect that it is during this 5 million year period that the sea lions developed as well.

Things have probably changed a lot in this area of paleontology since this paper was published in 1986, but unfortunately I can't seem to access most of these papers.  Callorhinus gilmorei still seems to be a valid taxon, however, as do Thalassoleon and Pithanotaria.  Hopefully, new fossils will yield more interesting results regarding these creatures very soon!  

Unless otherwise noted, the photo credit for all of these pictures in the post go to ZooBorns, either this post HERE or HERE.  

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Works Cited:

Dinosaur Provincial Park

As we talked about IN A PREVIOUS POST, dinosaurs are pretty big in Canada.  A large number of dinosaur species have been discovered up there, and one of the best places to find dinosaurs is a place near Calgary in Alberta called Dinosaur Provincial Park.  As a matter of fact, Dinosaur Provincial Park is a UNESCO World Heritage Site, along with 981 other properties "which the World Heritage Committee considers as having outstanding universal value."  Other famous sites include the Great Barrier Reef in Australia; the Galápagos Islands; Stonehenge; the Grand Canyon; and "Memphis and its Necropolis," the site of the Great Pyramids and the Great Sphinx of Giza!  Just to name a few.  Do you get the idea, though?  Dinosaur Provincial Park is kind of a big deal!

But why?  What makes a bunch of badlands with some dinosaur bones in them so important to Canada, much less a committee dedicated to protecting such international treasures as the Great Barrier Reef and the Great Pyramids?  What makes Dinosaur Provincial Park so GREAT?  (Get it?  Nevermind, it wasn't that funny anyways.)  Here's what the UNESCO website has to say about the park:

The property is unmatched in terms of the number and variety of high quality specimens, over 60 of which represent more than 45 genera and 14 families of dinosaurs, which date back 75-77 million years. The park contains exceptional riparian habitat features as well as "badlands" of outstanding aesthetic value.
The committee also included two main criterion that show why the park is so important:

Criterion (vii): Dinosaur Provincial Park is an outstanding example of major geological processes and fluvial erosion patterns in semi-arid steppes. These "badlands" stretch along 24 kilometers of high quality and virtually undisturbed riparian habitat, presenting a landscape of stark, but exceptional natural beauty.


Criterion (viii): The property is outstanding in the number and variety of high quality specimens representing every known group of Cretaceous dinosaurs. The diversity affords excellent opportunities for paleontology that is both comparative and chronological. Over 300 specimens from the Oldman Formation in the park including more than 150 complete skeletons now reside in more than 30 major museums.

Wow. Well that's a pretty big deal!  According to the website, between 1979 and 1991, a grand total of around 23,347 fossils were collected, including an amazing 300 dinosaur skeletons!  As mentioned above, the dinosaur skeletons represent every known group of Cretaceous dinosaurs.  (I assume that they mean every group that is known to live in North America at the time.)  Not only does the sheer amount of fossils allow for a more complete view of an extinct ecosystem, new dinosaurs and other animals have been discovered there, as well as potential behavior that can be inferred from the fossils! 

During the Late Cretaceous North America was divided by the Western Interior Seaway, a shallow, continental sea.  (To learn more about the seaway, check out a recent post I did on it by clicking HERE).  In Dinosaur Provincial Park, you can find the remains of both ocean going animals and land dwellers, as well!  The park is, of course, famous for its dinosaurs (as you could probably tell from its name).  But many of the marine creatures entombed in the rocks there and in the surrounding area are pretty awesome, as well!  For example, Hybodus, an interesting shark!  

Before we get to the dinosaurs, let's check out a few other cool creatures found in the park!  One of these is a creature we mentioned in a previous post: the post entitled "There Be Dragons," all about the monitor lizards!  In the post, I had a picture of a prehistoric monitor lizard named Palaeosaniwa attacking a flock of Ornithomimus.  Well, both of these creatures have been found in the park!  Below is the picture, created by talented paleo-artist James Field!  You can check out his website HERE!

Many animals have been discovered in the park, including turtles, crocodilians, and a ton of plants, but the only other non-dinosaur we are going to look at for now is a small little primitive marsupial mammal called Eodelphis!  Eodelphis, whose name means "early opossum," is thought to have weighed a little over a pound which, astonishingly, means that it was one of the largest mammals of its time!  It is thought to be related to Didelphodon, another Mesozoic marsupial mammal, who we shall meet in an upcoming post!

Now for the dinosaurs!  I'm going to start with an animal called Centrosaurus.  A ceratopsian dinosaur (just like Triceratops), thousands of individuals specimens of Centrosaurus have been discovered in a massive bonebed that extends for hundreds of meters!  While paleontologists disagree as to exactly what killed all of these animals, and in such immense numbers, the prevailing theory is that this was a herd of animals that drowned while trying to cross a river.  The individuals that make up the herd vary widely in age, which is one of the lines of evidence which supports the herd idea.  This is important evidence for paleontologists, as it indicates that these animals lived in groups!  

Another dinosaur that is found in the park is the small pachycephalosaur called Stegoceras, who is not to be confused with the similarly named and much more famous Stegosaurus!

Here is another fun dinosaur, called Chirostenotes!  This oviraptorosaur was first found in the park, and is definitely quite funky looking!

Dromaeosaurus, a distant cousin of Chirostenotes and a closer relative of the famous Velociraptor, was also first discovered in the park!

Just as Dromaeosaurus has been pushed from the limelight by Velociraptor, so too has Daspletosaurus been pushed by Tyrannosaurus!  Daspletosaurus is a tyrannosaur as well, and was first discovered in (surprise surprise) Dinosaur Provincial Park!  Two more Dinosaur Provinicial Park natives (and firsts) are Euoplocephalus, one of the tank-like ankylosaurs, and Parasaurolophus, a hadrosaur or duck-billed dinosaur!

I can't WAIT to visit the park one day!  In the meantime, HERE is a link to the park's website so you, too can plan your visit!

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Why Did The Great Auk Become Extinct?

Question:  Why did the Great Auk become extinct?

Answer:  Primarily because of human exploitation for its feathers and meat.

For those of you who are unfamiliar with the great auk (Pinguinus impennis), this penguin-like creature (a product of convergent evolution) inhabited the North Atlantic Ocean in the Northern Hemisphere, and became extinct mid-way through the 1800s.  The great auk was intensely hunted by humans in European waters for their down feathers, which were actually used in both pillows and hats, as well as for food.  (Not the down feathers, mind you, but the meat of the bird and its eggs).  It wasn't until 1553, around the time that the nesting sites of the great auk had been all but eliminated on the European side of the Atlantic, that the great auk first became officially protected.  In 1775, people who had broken a law forbidding people from killing the great auk for its feathers were actually beaten publicly! 

Following the local extinction (an extinction of a population of animals in one place, but not an extinction of the animal species as a whole) of the great auk in Greenland in 1815, the sole remaining breeding site of the great auk was a small, volcanic island.  Off of the coast of Iceland, the island was dubbed "Geirfuglasker," after the Norse term for "great auk," "Geirfugl."  In 1830, however, the great auk population on Geirfuglasker came under siege by two elemental forces that it had no hopes of combating: an underwater volcanic eruption and a subsequent earthquake, which combined to destroy the island, terminating most of the rest of the great auks.

Those few auks that survived relocated to the nearby island of Eldey.  Eldey was quite easily accessible to man, however, and the last human-led hunt of the great auk occurred on June 3rd, 1844.  On this last great hunt, a pair of these birds were killed, beaten to death, and their egg was destroyed. 

The last sighting accepted by the IUCN to be legitimate was in 1852 off of the coast of Newfoundland in Canada.
The closest living relative of the great auk is believed to be the razorbill (Alca torda), seen below.

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A Skunky Surprise and the Mimicry of the Steller's Jay

 

 

 

 

 

 

Last night on Primos we didn't get any stupid little kids trying to steal the camera, and we also unfortunately didn't get any foxes, but we did get not one, not three, but TWO visits from a skunk last night!  I have absolutely no idea if the skunks were the same, or whether they were two completely different skunks.  Another, but slightly less alternative, is that there was a whole band of the little, sometimes stinky creatures, and they were all taking turns on jumping into the camera every 13 or so seconds.  (The camera takes 5 pictures in about two or three seconds for every activation of the motion sensor, and then waits another ten seconds before it will again activate).  Again, this hypothesis is slightly less likely, but not impossible.  So enjoy these pictures of the skunk/two skunks/band of skunks!  I also nabbed a picture of the "Least Concern" Steller's jay, a very attractive type of jay (hey, what Jay isn't?) native to the coniferous forests in and west of the Rocky Mountains in North America.

The Steller's jay is quite an interesting little creature, for many different reasons, so let's take a little look-see, shall we?  Let's start off with what I believe to easily be the most interesting tidbit of Steller's jay facts: it will mimic hawks!  The Steller's jay is omnivorous, eating about two-thirds plants, and the other third meat.  So when other birds are at an area where the Steller's jay wishes to feed, it will imitate the cry of the red-tailed hawk, or the red-shouldered hawk.  This, of course, would startle the other animals and cause them to flee, leaving the area devoid of competition from most other animals.  According to my bird book, the blue jay also "imitates hawks expertly."  Another excellent example of avian mimicry! 

The Steller's jay is also the provincial bird of British Columbia, in Canada, and is named for the Georg Wilhelm Steller, the German naturalist who first discovered the bird in 1741.  I wonder whether anyone ever told him that he spelled "George" wrong....

Steller has had numerous animals named after him, including: the Steller's sea cow (an extinct relative of the manatee), the Steller's sea lion, the Steller's sea eagle, and the Steller's eider (which is a type of duck).  He did much of his work in Russia, but is also considered to be a "pioneer of Alaskan natural history."  What a bro!

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Acrobatic Felines: The Serval

This birthday post goes out to Maiji Castro, happy birthday Maiji!  If you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animal, and I will do my best to get a post in!

Today, the serval is going to be added to our pantheon of acrobatic felines!  The serval (Leptailurus serval) is another one of those mid-sized cats, like the caracal, bobcat, and lynx, and is actually closely related to the caracal!  DNA studies place the serval in what is frequently referred to as the "Caracal Lineage," with the serval being the basal-most, or the earliest to split off, of these three cats.  The other two are, of course, the caracal, and its closest relative, the African golden cat.

So that tells us about the serval's phylogenetic position in the feline family tree, but what else do we know about this interesting creature?  And how is it so acrobatic?  Well, the serval, much like the caracal, is a jumper, perhaps not quite as high of a leaper, but nevertheless an amazingly nimble cat.  It's incredible jumps are assisted by its long legs: in fact, the serval has, in relation to its body size, the longest legs of any feline.  To see the incredible leaps of the serval, click on the link below!

A Pretty Awesome Serval Jump!

The serval is labeled "Least Concern" by the IUCN, and has a very wide distribution across the continent of Africa, excluding deserts (like the Sahara) and the equatorial jungles of the Democratic Republic of the Congo and the neighboring countries.  The serval once inhabited the countries of Tunisia, Algeria, and Morocco, as well, but seems to have been extirpated (caused to go extinct in one country as opposed to extinct overall; a local extinction).  It is also now found in Tunisia again, but was reintroduced there by humans.

Four albino servals have been documented throughout the years, all of which were born in captivity.  One was born in Canada in the early '90s, but died just a week or two after birth.  The other three were all born at Florida's excellent cat sanctuary, Big Cat Rescue.  (If you want to see a ton of really, really cute pictures, click on this link HEREEEEEEEEEEEEEE to their Facebook page.  Trust me, you will NOT be disappointed!)  One of these three died a few years back, but they still have two!  First is Pharaoh, who is featured in the picture below, and Tonga, who is featured in all of the rest of the pictures, and who recently overcame nose cancer.  Enjoy!

Antlers Vs. Horns, Part 2: Horns

A horn, unlike an antler, is attached to an animal.  It consists of a bony core, a projection of the bone of an animal, and is covered by a layer of keratin (your fingernails are composed of keratin).  Also unlike an antler, that falls off easily and annually, a horn, if it is broken off, will never grow back the same way.  That is why poachers have to kill rhinos (who have horns) to actually take their horns, as opposed to just letting them fall off.

Many different types of animals have horns.  Let's take a look at a few of these creatures.

The members of the family "Giraffidae," which includes the giraffe and the okapi, both have horn-like things on their heads, called "ossicones."

The members of the family "Rhinocerotidae," or the rhinos, have horns that are composed solely of keratin, and do not have the bone core typical of many horns.  The horns of the rhinos also grow continuously.

Some of the members of the family "Chamaeleonidae," or the chameleons, often have horns projecting out of their skulls, which are covered in a layer of keratin.

And, of course, the members of the family "Ceratopsidae," a group of marginocephalian dinosaurs, have horns projecting out of their skulls. 
Below is a short list of some of the more famous Ceratopsian dinosaurs.

Famous examples of Ceratopsian Dinosaurs (or "Ceratopsians That I Have Heard Of):

1. Triceratops - (Colorado, Montana, and Wyoming, U.S.; Alberta and Saskatchewan, Canada)
2. Arrhincoceratops - (Alberta, Canada)
3. Torosaurus - (Montana, North Dakota, South Dakota, Utah, and Wyoming, U.S.; Saskatchewan, Canada)
   
4. Monoclonius - (Montana, U.S.; Alberta, Canada)
5. Chasmosaurus - (Alberta, Canada)
   
6. Centrosaurus - (Alberta, Canada)
7. Styracosaurus - (Montana, U.S.; Alberta, Canada)
   
8. Achelousaurus - (Montana, U.S.)
9. Pentaceratops - (New Mexico, U.S.)
10. Vagaceratops - (Alberta, Canada)
    
11. Diabloceratops - (Utah, U.S.)
12. Albertaceratops - (Montana, U.S.; Alberta, Canada)
13. Einiosaurus - (Montana, U.S.)
14. Anchiceratops - (Alberta, Canada)
15. Mojoceratops - (Alberta and Saskatchewan, Canada)
16. Pachyrhinosaurus - (Alaska, U.S.; Alberta, Canada)
17. Kosmoceratops - (Utah, U.S.)
18. Medusaceratops (Montana, U.S.)
19. Utahceratops - (Utah, U.S.)

Keep in mind that the tusks seen in elephants, mammoths, walruses, and hippos, despite being superficially similar to horns, are actually greatly enlarged teeth!

The Fauna of South Carolina: Cetaceans, Foxes and Otters

Here is the second in the "Fauna of South Carolina series."  Today, we are going to take a brief look at some of the cetaceans, foxes and otters that we saw while we were down there, either in the wild or in zoos.  Let's start with the otters.

River Otters ("Least Concern" by the IUCN) at Brookgreen Gardens

We saw both the otters and the foxes at Brookgreen Gardens, at their Lowcountry Zoo.  Not quite as cool as the foxes in my opinion were the river otters.  They were definitely really cool, as they were running around and playing a great deal, and we had a great view of them.  I'm not sure if I have ever seen otters playing so much, and seen it so well.  It was definitely quite a treat!  The range of the river otter is slightly weird; encompassing Oregon, Washington, and parts of California,and then extending throughout most of Alaska and Canada, and then coming down along the east coast of the United States, down to Florida, Mississippi, Alabama and Louisiana.

Gray Fox in tree

Prior to that, we had visited the fox exhibit.  We were looking for red fox and gray fox.  If I recall correctly (which I often don't), we were having trouble seeing the gray foxes, when I noticed something moving in one of the trees.  It was the gray fox!  I had no idea that foxes climb trees!  In fact, other than the raccoon dog found in Asia, I believe not many other canids in fact do climb. 

Gray fox in tree

Gray fox in tree

Gray fox in tree

 The gray fox, like the river otter, is labeled "Least Concern" by the IUCN.  Its range stretches from most of North America, down through Mexico, Central America, and into bits of South America.  The Channel Island Fox (a very interesting animal that we will by all means talk about at some point soon) is almost certainly descended from gray fox on the mainland. 

Instead of doing the cetaceans like we previously planned today, I think we should do them some other time.  See you later!

This post is part of "The Fauna of South Carolina" series.  For the rest of the posts in this series, click HERE.

Garden City Beach on Dwellable

Animal Spotlight: The Polar Bear

The polar bear (Ursus maritimus) is the world's largest extant, terrestrial carnivore, with males growing up to 1,500 pounds.  Like many animals that spend a good amount of time in the water, their feet are partially webbed to aid in swimming.  Although the fur of the polar bear is white, to help it blend into the ice and snow when it is hunting seals, its skin underneath is black, to aid in heat absorption.

In the picture above, it certainly looks like the polar bear is just enjoying itself, and having a good time.  While both of these may be true, the polar bear is actually cleaning its fur, presumably after a kill, given the blood-stained snow off in the left of the picture.  Below the picture is a link to a video clip from BBC's "Planet Earth," narrated by one of my personal heroes, David Attenborough.  In the video, make sure to watch for the fur cleaning.

This is the link to the Planet Earth link: https://www.youtube.com/watch?v=OwZH_aT0FGI

The polar bear, due to its immense size and lack of natural predators, fears nothing, humans included.  This, coupled with a natural, and insatiable, curiosity, often brings bears and humans into contact.  The video clip below is from another BBC show, called "Polar Bear: Spy on the Ice."  I first saw this show when we were in South Carolina this summer, and found it really interesting!  This clip is one of my favorite parts from it.

Polar Bears Attacking Spy Cameras:  http://www.youtube.com/watch?v=DvduCPXO_FE

Finally, we have another interesting YouTube video that I discovered today.  Watch and enjoy!

https://www.youtube.com/watch?v=JE-Nyt4Bmi8

The polar bear's range covers five different countries: Russia, Denmark owned Greenland, Norway owned Svalbard, Alaska, and Canada.

The Fox's Animal Magnetism

For a while now, it has been thought that birds could see the magnetic field, in order to help them migrate.  It has been hypothesized that, when they are facing north, they can see a little blurry patch at the bottom of their eye.  If they are facing east or west, then they can't see the patch, so they know where to put the patch in their field of vision to get where they want to go.  Recent research by a Czech team of scientists seems to indicate that the red fox can also use the magnetic field, but for a different purpose: hunting.

The red fox (Vulpes vulpes) ("Least Concern" by the IUCN) has the largest geographical distribution of any member of the Carnivora, with habitat on all of the continents except for South America and Antarctica.  In North America, it inhabits the United States and Canada, in Europe and Asia it lives almost everywhere, and in Africa it lives in Morocco, Algeria, Tunisia, Egypt, Sudan, and Libya.  Not only does it possesses the range shown in the map below, it has been introduced to Australia, where, like the Dingo, it poses a threat to native species.

The red fox hunts by leaping up into the air, and coming down right on top of its prey, literally (for the prey, at least) appearing out of nowhere.  But how to pinpoint its jump?  The answer lies in the magnetic field, which is visible to the foxes.  But how does this work?  Out of all of the explanations set forth by various journals and such, I thought the explanation from Nature was easiest to understand.  Here's what they have to say:

"Think of a laser pointer attached to you that always points slightly downwards in the same direction. Now think of some object on the ground. If you walk towards the object until the laser spot is on top of it you know that object is a set distance away."

Generally, it was thought that foxes would pinpoint their location solely using their very acute sense of hearing.  But then the Czech team found that, when the red fox was leaping in a northerly direction, 74% of the attacks were successful, while the leaping attacks in other directions had the success rate of a mere 18%.  That's a very big difference, and seems to point to the magnetic field theory.

A picture of the red fox outside of the house that our friends the Beckleys rented in Breckenridge one summer.  Awesome place to stay, especially if you are looking to escape the summer heat!  Photo Credit: Julie Neher

East Breckenridge on Dwellable

Animal Spotlight: The Bobcat

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The bobcat is one of three main felines that lives in North America, the others being the Canadian lynx and the mountain lion.  (Although other cats, like the jaguar, jaguarundi and ocelot, do occasionally make it up to Texas and Mexico, generally they just live in Central and South America).  Labeled "Least Concern" by the IUCN, the bobcat averages around three feet in length, and is named such for the short, "bobbed" tail.

A bobcat at The Living Desert in Palm Desert, California.  Note the short, stubby tail.

The bobcat is quite adaptable; it inhabits almost every single environment that the Continental United States has to offer, as well as most of Mexico.  There are thirteen recognized sub-species of bobcat.  Furthermore, despite its size, can be strong enough to take down small deer.  Here is a link to a video about a bobcat that I found to be quite interesting.

http://www.youtube.com/watch?v=S5BfNtim148

When we went camping last week, twice did we see paw prints that looked too small to be mountain lion prints, and were most likely bobcat prints.  I was quite excited; unfortunately (but not surprisingly) we didn't see any of the cats themselves.  Here is one picture from each of the times we saw the tracks. 

East Palm Desert on Dwellable

Convergent Evolution: Hesperornis and Penguins

Everyone who is reading this blog, and most people who aren't, have heard of penguins, and know, more or less, what they look like.  However, most people have no idea what a Hesperornis is, which is entirely forgivable.  What is especially interesting about Hesperornis is that it was really the "original penguin," in the loosest sense of the terms.

If not for the captions below each picture, these two animals would most likely be quite difficult to tell apart.  One major difference between the two birds is in the mouth: Hesperornis had teeth, a feature which no modern birds possesses.  Another major, but non-skeletal difference, between the two birds is that Hesperornis died out 78 MYA, during the Late Cretaceous.  Its remains have been found in the United States (Kansas), Canada, and Russia.

The similarities between Hesperornis and modern day penguins is called "Convergent Evolution," a fascinating topic which we will undoubtedly touch upon numerous times.  According to Science Daily, convergent evolution is, "In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches."  In English, when two animals, not necessarily closely related at all, evolve similar features that serve the same purpose.

An (excellent) drawing of the skull of Thylacosmilus

 Another example which we have already talked about is the long, saber-like canines that evolved in both the saber-toothed cats, such as Smilodon, and the South American marsupial carnivore Thylacosmilus.

 This post is part of the "Convergent Evolution" series.  For the rest of the posts in this series, click HERE.